JP4926597B2 - Memory device and semiconductor device - Google Patents

Description

  The present invention relates to a memory device and a semiconductor device including a memory element formed using an organic compound.

  In recent years, semiconductor devices are required to be manufactured at low cost. For this reason, development of electronic devices using organic compounds in control circuits, memory circuits, etc. has been widely conducted, and development of organic EL (Electro-Luminescence), organic TFT (thin film transistor), organic semiconductor laser, etc., which are light emitting elements. Has been made.

Furthermore, a memory device having a memory element using an organic compound has been developed, and the generation of internal light in the memory element causes an interaction in the organic compound of the memory element, which causes a chemical change and causes a change in the memory element. There has been proposed a method of writing data by changing conductivity. Specifically, chain separation of conjugated molecules by the effect of internal light, and chemical reactivity of chemical species added by the effect of light are increased, attacking conductive materials in the cell, and reducing the bulk conductivity By doing so, an example of writing data is described (for example, Patent Document 1).
JP-T-2001-503183 (page 10, FIG. 6)

  However, in the storage device as shown in Patent Document 1, when writing data by chain separation of conjugated molecules by generation of internal light, it is difficult to control products generated by chain separation. The reaction product is formed. In addition, radicals are generated when writing data using a technique that lowers the conductivity of the bulk by attacking the conductive material in the cell by chemical species whose chemical reactivity has been enhanced by the generation of internal light. The reaction proceeds. For this reason, it is difficult to control the termination of the reaction, and as a result, it is difficult to form an arbitrary product. As a result, there is a problem in that the conductivity of the memory element after writing cannot be controlled, the writing result varies, and the writing success rate decreases.

  In addition, as a storage device, DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), FeRAM (Ferroelectric Random Access Memory Memory), Mask ROM (Read Only Memory Memory). Electrically Erasable and Programmable Read Only Memory), flash memory, and the like. Among these, DRAM and SRAM are volatile storage devices, and data is erased when the power is turned off. Therefore, it is necessary to write data every time the power is turned on. FeRAM is a nonvolatile memory device, but a manufacturing process is increased because a capacitor element including a ferroelectric layer is used. Although the mask ROM has a simple structure, it is necessary to write data in the manufacturing process and cannot be additionally written. Although EPROM, EEPROM, and flash memory are non-volatile storage devices, the number of manufacturing steps increases because an element including two gate electrodes is used.

  In view of the above problems, the present invention provides a semiconductor device with high writing reliability and low cost. In addition, a semiconductor device including a nonvolatile memory element that can additionally record data other than at the time of manufacture and can prevent forgery or the like due to rewriting is provided.

  A memory element included in a memory device of the present invention is formed between a first conductive layer, a second conductive layer, a first conductive layer, and a second conductive layer, and recycles electrons and holes. A layer containing an organic compound having a photosensitized redox agent that can be excited by binding energy and a substrate that can react with the photosensitized redox agent.

  Note that the layer including an organic compound may include a light-emitting material.

  The memory element included in the memory device of the present invention applies a voltage to the first conductive layer and the second conductive layer, and uses recombination energy by recombination of holes and electrons, or light emission energy, The photosensitized redox agent is brought into an excited state, and at least a part of the substrate is subjected to a photosensitized redox reaction using the excited photosensitized redox agent to produce a reaction product having a conductivity different from that of the substrate. And writing data.

  Electrons and holes generated by applying a voltage to the first conductive layer and the second conductive layer of the memory element are at least one selected from a photosensitized redox agent, a substrate, or a light-emitting material. Recombination takes place, and the photosensitized redox agent becomes excited by the recombination energy or emission energy generated by the recombination, and at least a part of the substrate is photosensitized by the photosensitized redox agent in the excited state. A redox reaction occurs and a product is produced.

  Note that the layer containing an organic compound may be formed by stacking a layer formed using a light-emitting material and a layer formed using a photosensitized redox agent and a substrate.

  Further, by using one electrode of the light-emitting element and one electrode of the memory element as a common electrode and forming the common electrode with a light-transmitting material, light emitted from the light-emitting element The photosensitized redox agent can be irradiated by irradiating the photosensitized redox agent.

  Further, at least one of a charge injection layer and a charge transport layer may be provided between the first conductive layer and the layer containing an organic compound. Similarly, at least one of a charge injection layer and a charge transport layer may be provided between the second conductive layer and the layer containing an organic compound. In the case where the first conductive layer functions as an anode, at least one of a hole injection layer and a hole transport layer may be provided between the first conductive layer and the layer containing an organic compound. In the case where the second conductive layer functions as a cathode, at least one of an electron injection layer and an electron transport layer may be provided between the second conductive layer and the layer containing an organic compound.

  In addition, the semiconductor device including the above memory device may include a conductive layer functioning as an antenna and a transistor electrically connected to the conductive layer. Further, a diode connected to the first conductive layer or the second conductive layer may be included.

  In the semiconductor device, the memory cell array and the writing circuit may be provided over a glass substrate or a flexible substrate, and the writing circuit may be formed using a thin film transistor.

In the semiconductor device, the memory cell array and the write circuit may be provided over a single crystal semiconductor substrate, and the write circuit may be formed of a field effect transistor.

Furthermore, the semiconductor device may include one or more of a read circuit, a power supply circuit, a clock generation circuit, a data demodulation / modulation circuit, a control circuit, and an interface circuit in addition to the write circuit.

  Note that typical examples of the semiconductor device of the present invention include a wireless chip typified by an ID chip, a wireless tag, an RFID (Radio frequency identification) tag, an IC tag, and the like.

  The memory element of the present invention excites a photosensitized redox agent by the recombination energy of electrons and holes, performs a photosensitized redox reaction of a substrate by the excitation energy, and generates a reaction product to generate a memory element. Data is written by changing the electrical resistance. For this reason, writing can be controlled, and as a result, variations in writing can be reduced. In addition, the write success rate can be increased.

  In addition, the memory element and the semiconductor device can be downsized because the memory element itself emits light and data can be written using the light emission without providing an external light irradiation device for writing. High integration is possible. In addition, since the photosensitized redox agent can be excited without losing energy emitted from the light emitting material, writing can be performed with high energy efficiency.

  In addition, since the memory device and the semiconductor device of the present invention can write (append) data other than at the time of chip manufacturing and cannot rewrite data, a memory device and a semiconductor device capable of preventing forgery by rewriting are obtained. be able to. In addition, since the memory device and the semiconductor device of the present invention include a memory element having a simple structure in which a layer containing an organic compound is sandwiched between a pair of conductive layers, an inexpensive semiconductor device can be provided.

  Embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below. Note that in the structures of the present invention described below, the same reference numerals are used in common in different drawings.

  In the embodiment, the structure of the memory element is described with reference to a model diagram. For this reason, the size, thickness, and shape of each component of the memory element may be different from actual ones.

(Embodiment 1)
In this embodiment, structural examples of memory elements included in the memory device of the present invention will be described with reference to drawings.

  As shown in FIG. 1, the memory element of this embodiment mode includes a first conductive layer 101, a layer 110 containing an organic compound in contact with the first conductive layer, and a second conductive layer in contact with the layer containing an organic compound. And layer 103. The layer 110 containing an organic compound includes a photosensitized redox agent 106a that can be excited by recombination energy of electrons and holes, and a substrate 105 that can react with the photosensitized redox agent.

  By making the potential of the first conductive layer 101 higher than that of the second conductive layer 103, a current flows and holes and electrons are recombined in the layer 110 containing an organic compound. Therefore, the first conductive layer 101 functions as an anode, and the second conductive layer 103 functions as a cathode. In this embodiment, an example in which holes and electrons recombine in the photosensitized redox agent 106a of the layer 110 containing an organic compound is described.

  As the first conductive layer 101, a material having a work function in the range of 3.5 eV to 5.5 eV can be used. Specifically, in addition to transparent electrodes such as indium tin oxide (ITO) and indium tin oxide with addition of silicon, titanium, molybdenum, tungsten, nickel, gold, platinum, silver, aluminum, and alloys thereof Can be used. In particular, titanium, molybdenum, aluminum, or an alloy thereof is a general-purpose metal that is often used for wiring and the like. By using these as the first conductive layer 101, an inexpensive memory element can be provided. .

  The layer 110 containing an organic compound includes a substrate 105 and a photosensitized redox agent 106a.

  Examples of the photosensitizing redox agent 106a include compounds having a structure having a strong redox power in an excited state such as an alloxazine ring or chlorophyll in the structure, and typically include lumichrome, alloxazine, lumiflavin, and flavin mononucleotide. And tetramethyleneparaphenylenediamine. The photosensitized redox agent 106 a becomes an oxidizing agent or a reducing agent depending on the reaction conditions and the combination with the substrate 105.

  The substrate 105 is a compound that is decomposed by a photosensitized oxidation-reduction reaction, specifically, oxidation of alcohol, oxidative cleavage of alkene, cyclization reaction, ring-opening reaction, or the like, or a compound whose structure is changed, or , A compound capable of dedoping a metal by a photosensitized redox reaction. Representative examples of compounds that are decomposed by a photosensitized redox reaction, such as oxidation of alcohol, oxidative cleavage of alkenes, cyclization reaction or ring-opening reaction, or compounds that undergo structural changes include ascorbic acid, guanosine, dibenzofuran, 11-cis-3,4-didehydroretinal, uridine, thymidine, etc. are mentioned.

  The substrate 105 is oxidized or reduced depending on the reaction conditions and a combination with a photosensitized redox agent.

  In addition, examples of the compound capable of dedoping a metal by a photosensitized redox reaction include fullerene having a central metal, chlorophyll, phthalocyanine, or hemin. As the central metal, aluminum (Al), titanium (Ti), chromium) Cr), vanadium (V), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu) ), Zinc (Zn), zirconium (Zr), niobium (Nb), molybdenum (Mo), Ru (ruthenium), rhodium (Rh), palladium (Pd), silver (Ag), cadmium (Cd), indium (In ), Tin (Sn), cesium (Cs), hafnium (Hf), tantalum (Ta), tungsten (W), osmium (Os), iridium (Ir), platinum (Pt), gold (Au), lead (Pb) ), Bismuth (Bi) and the like.

  The second conductive layer 103 can be formed using a material similar to that of the first conductive layer 101. Alternatively, a metal having a low work function such as lithium, magnesium, calcium, barium, or an alloy thereof may be used.

  Next, data writing in the memory element of this embodiment will be described. As shown in FIG. 1A, when a voltage is applied to the first conductive layer 101 and the second conductive layer 103 to generate a potential difference between the two conductive layers, the photosensitized oxidation of the layer 110 containing an organic compound is performed. Holes and electrons recombine in the reducing agent 106a, and the photosensitized redox agent is in the excited state 106b as shown in FIG.

  Next, the reaction of at least a part of the substrate 105 is promoted by the excitation energy 100a of the photosensitized redox agent in the excited state 106b, and a product 107 is generated as shown in FIG. Typical examples of the product include a substance in which the substrate is decomposed, a substance in which the substrate is structurally changed, or a substance in which a metal is dedoped. On the other hand, the photosensitized redox agent in the excited state 106b returns to the photosensitized redox agent 106a before the excited state.

  The product 107 of the substrate 105 becomes an oxide when the substrate is oxidized, and is a reduced product when the substrate is reduced, and has a conductivity different from that of the substrate 105. Therefore, a voltage is applied to the first conductive layer and the second conductive layer, and the product 107 is generated, whereby the electric resistance of the memory element changes. Typically, an increase in resistance that causes insulation or a decrease in resistance that causes short-circuiting can be given. That is, a voltage is applied to the first conductive layer 101 and the second conductive layer 103, the photosensitized redox agent of the layer containing an organic compound is excited, and the substrate is oxidized or reduced by the excitation energy. To produce a product. Data can be written by the change in the electrical resistance of the memory element which occurs as a result. In some cases, heat is generated by the photosensitized oxidation-reduction reaction of the substrate, and the shape or film thickness of the layer is simultaneously changed by the heat. With this change, data can be written by a change in electrical resistance of the memory element.

  Note that in the case of reading data from a memory element, data can be read by reading a difference between the electric resistance of the memory element before writing and the electric resistance of the memory element after writing.

  The memory device of the present embodiment excites the photosensitized redox agent by the recombination energy of electrons and holes in the photosensitized redox agent, and causes the specific photosensitized redox reaction by the excitation energy. Data is written by changing the electrical resistance of the memory element. At this time, the reaction product can be controlled. As a result, variation in writing can be reduced, and the writing success rate can be increased.

(Embodiment 2)
In this embodiment, a memory element in which recombination of holes and electrons occurs in a substrate included in a layer containing an organic compound as compared with Embodiment 1 will be described with reference to FIGS.

  The memory element in this embodiment is formed of a first conductive layer 101, a layer 110 containing an organic compound in contact with the first conductive layer, and a second conductive layer 103 in contact with the layer containing an organic compound.

  In this embodiment mode, the layer 110 containing an organic compound includes a substrate 105 and a photosensitized redox agent 106a. The first conductive layer 101, the second conductive layer 103, the substrate 105, and the photosensitized redox agent 106a can be formed using the same materials as those in Embodiment 1.

  Next, data writing in the memory element of this embodiment will be described. As shown in FIG. 2A, when a voltage is applied to the first conductive layer 101 and the second conductive layer 103 to generate a potential difference between the two conductive layers, the substrate 105 of the layer 110 containing an organic compound is positive. The holes and electrons recombine to generate recombination energy 100b.

The recombination energy moves to the photosensitized redox agent 106a, and as shown in FIG. 2B, the photosensitized redox agent is in an excited state 106b.

  Next, the reaction of at least a part of the substrate 105 is promoted by the excitation energy 100a of the photosensitized redox agent in the excited state 106b, and a product 107 is generated as shown in FIG. A typical example of the product is the same as the product 107 in the first embodiment.

  The substrate product 107 has a different conductivity than the substrate 108. Therefore, voltage is applied to the first conductive layer and the second conductive layer, and the product 107 is generated, so that the electrical resistance of the memory element changes as in the first embodiment. Typically, an increase in electrical resistance that causes insulation or a decrease in electrical resistance can be given. As described above, data can be written by a change in electrical resistance due to voltage application of the first conductive layer 101 and the second conductive layer 103.

  Note that in the case of reading data from a memory element, data can be read by reading a difference between the electric resistance of the memory element before writing and the electric resistance of the memory element after writing.

  The memory element of the present embodiment excites the photosensitized redox agent by the recombination energy of electrons and holes in the photosensitized redox agent, and causes a specific photosensitized redox reaction by the excitation energy. Data is written by changing the electrical resistance of the memory element. At this time, it is possible to control the reaction product, and as a result, variation in writing can be reduced, and the writing success rate can be increased.

(Embodiment 3)
In this embodiment, as compared with Embodiments 1 and 2, a structural example of a memory element including a light-emitting material in a layer containing an organic compound will be described with reference to drawings.

  The memory element of this embodiment is formed of a first conductive layer 101, a layer 102 containing an organic compound in contact with the first conductive layer, and a second conductive layer 103 in contact with the layer containing an organic compound.

  In this embodiment mode, the layer 102 containing an organic compound includes a substrate 105, a photosensitized redox agent 106 a, and a light-emitting material 104. The first conductive layer 101, the second conductive layer 103, the substrate 105, and the photosensitized redox agent 106a can be formed using the same materials as those in Embodiment 1.

  The light-emitting material 104 may be any organic compound that has high energy transfer efficiency to the photosensitized redox agent regardless of the light emission quantum efficiency. Therefore, at least one selected from a light emitting material, a hole transporting material, a hole injecting material, an electron transporting material, and an electron injecting material can be used as appropriate. Here, a material having high emission quantum efficiency is referred to as a light emitting material.

Examples of the light-emitting material include 9,10-di (2-naphthyl) anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di (2-naphthyl) anthracene (abbreviation: t-BuDNA), 4 , 4′-bis (2,2-diphenylvinyl) biphenyl (abbreviation: DPVBi), coumarin 30, coumarin 6, coumarin 545, coumarin 545T, perylene, rubrene, periflanthene, 2,5,8,11-tetra (tert-) (Butyl) perylene (abbreviation: TBP), 9,10-diphenylanthracene (abbreviation: DPA), 5,12-diphenyltetracene, 4- (dicyanomethylene) -2-methyl-6- [p- (dimethylamino) styryl] -4H-pyran (abbreviation: DCM1), 4- (dicyanomethylene) -2-methyl-6- [2- (julolidine- 9-yl) ethenyl] -4H-pyran (abbreviation: DCM2), 4- (dicyanomethylene) -2,6-bis [p- (dimethylamino) styryl] -4H-pyran (abbreviation: BisDCM), and the like. . In addition, bis [2- (4 ′, 6′-difluorophenyl) pyridinato-N, C ² ] (picolinato) iridium (abbreviation: FIrpic), bis {2- [3 ′, 5′-bis (trifluoromethyl) Phenyl] pyridinato-N, C ² } (picolinato) iridium (abbreviation: Ir (CF ₃ ppy) ₂ (pic)), Tris (2-phenylpyridinato-N, C ² ) iridium (abbreviation: Ir (ppy)) _3), (acetylacetonato) bis (2-phenylpyridinato--N, ^{C 2)} iridium (abbreviation: _Ir (ppy) 2 (acac)), (acetylacetonato) bis [2- (2'-thienyl ) pyridinato -N, ^{C 3]} iridium _{(abbreviation: Ir (thp) 2 (acac} )), ( acetylacetonato) bis (2-phenylquinolinato--N, ^{C 2)} iridium ( _Aka: such as 2 (acac)): Ir ( pq) 2 (acac)), (Ir (btp acetylacetonato) bis [2- (2'-benzothienyl) pyridinato -N, ^{C 3]} iridium (abbreviation) A compound capable of emitting phosphorescence can also be used.

Examples of the electron transporting material include tris (8-quinolinolato) aluminum (abbreviation: Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (abbreviation: Almq ₃ ), bis (10-hydroxybenzo [h] -quinolinato. ) Beryllium (abbreviation: BeBq ₂ ), bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (abbreviation: BAlq), bis [2- (2′-hydroxyphenyl) benzoxazolate] zinc (Abbreviation: Zn (BOX) ₂ ), bis [2- (2′-hydroxyphenyl) benzothiazolate] zinc (abbreviation: Zn (BTZ) ₂ ), bathophenanthroline (abbreviation: BPhen), bathocuproin (abbreviation: BCP), 2 -(4-Biphenylyl) -5- (4-tert-butylphenyl) -1,3,4-oxy Diazole (abbreviation: PBD), 1,3-bis [5- (4-tert-butylphenyl) -1,3,4-oxadiazol-2-yl] benzene (abbreviation: OXD-7), 2,2 ', 2''-(1,3,5-benzenetriyl) -tris (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 3- (4-biphenylyl) -4-phenyl-5- ( 4-tert-butylphenyl) -1,2,4-triazole (abbreviation: TAZ), 3- (4-biphenylyl) -4- (4-ethylphenyl) -5- (4-tert-butylphenyl) -1 , 2,4-triazole (abbreviation: p-EtTAZ) and the like, but is not limited thereto.

Examples of the electron injection material include alkali metal halides such as LiF and CsF, alkaline earth halides such as CaF ₂ , and alkali metal oxides such as Li ₂ O in addition to the electron transport materials described above. A very thin layer of insulator is often used. In addition, alkali metal complexes such as lithium acetylacetonate (abbreviation: Li (acac) and 8-quinolinolato-lithium (abbreviation: Liq) are also effective. Furthermore, the above-described electron transporting materials, Mg, Li, Cs, and the like are also effective. It is also possible to use a material in which a metal having a small work function is mixed by co-evaporation or the like.

Examples of the hole transporting material include phthalocyanine (abbreviation: H ₂ Pc), copper phthalocyanine (abbreviation: CuPc), vanadyl phthalocyanine (abbreviation: VOPc), and 4,4 ′, 4 ″ -tris (N, N-diphenylamino) triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), 1, 3,5-tris [N, N-di (m-tolyl) amino] benzene (abbreviation: m-MTDAB), N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1 '-Biphenyl-4,4'-diamine (abbreviation: TPD), 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: NPB), 4,4'-bis { N- [4-Di (m- Ryl) amino] phenyl-N-phenylamino} biphenyl (abbreviation: DNTPD), 4,4′-bis [N- (4-biphenylyl) -N-phenylamino] biphenyl (abbreviation: BBPB), 4,4 ′, 4 ″ -tri (N-carbazolyl) triphenylamine (abbreviation: TCTA) and the like can be mentioned, but the invention is not limited thereto. Among the compounds described above, aromatic amine compounds typified by TDATA, MTDATA, m-MTDAB, TPD, NPB, DNTPD, BBPB, TCTA, and the like are prone to generate holes and are a group of compounds suitable as organic compounds. It is.

As the hole injecting material, is effective phthalocyanine compound, phthalocyanine _{(abbreviation:} H 2 -Pc), copper phthalocyanine (abbreviation: Cu-Pc), vanadyl phthalocyanine (abbreviation: VOPc), or the like can be used. In addition, there is a material obtained by chemically doping a conductive polymer compound, and polyethylenedioxythiophene (abbreviation: PEDOT) or polyaniline (abbreviation: PAni) doped with polystyrene sulfonic acid (abbreviation: PSS) can also be used. . Also effective are inorganic semiconductor thin films such as molybdenum oxide (MoO _x ), vanadium oxide (VO _x ), nickel oxide (NiO _x ), and ultra-thin films of inorganic insulators such as aluminum oxide (Al ₂ O ₃ ). . In addition, 4,4 ′, 4 ″ -tris (N, N-diphenyl-amino) -triphenylamine (abbreviation: TDATA), 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenyl-amino] -triphenylamine (abbreviation: MTDATA), N, N'-bis (3-methylphenyl) -N, N'-diphenyl-1,1'-biphenyl-4,4'-diamine (Abbreviation: TPD), 4,4′-bis [N- (1-naphthyl) -N-phenyl-amino] -biphenyl (abbreviation: NPB), 4,4′-bis [N- (4- (N, An aromatic amine compound such as N-di-m-tolyl) amino) phenyl-N-phenylamino] biphenyl (abbreviation: DNTPD) can also be used. Furthermore, these hole transporting materials and substances exhibiting acceptor properties may be added to the hole injecting material. Specifically, 2,3,5,6-tetrafluoro, which is an acceptor for VOPc, may be added. A material to which -7,7,8,8-tetracyanoquinodimethane (abbreviation: F ₄ -TCNQ) is added or a material in which MoO _x as an acceptor is added to NPB may be used.

  Next, data writing in the memory element of this embodiment will be described. As shown in FIG. 3A, when a voltage is applied to the first conductive layer 101 and the second conductive layer 103 to generate a potential difference between the two conductive layers, a material having a light-emitting property of a layer containing an organic compound At 104, holes and electrons recombine.

  When the recombination energy 100b of the light-emitting material moves to the photosensitized redox agent 106a, as shown in FIG. 3B, the photosensitized redox agent 106a becomes an excited state 106b by the recombination energy, Has excitation energy.

  Next, the reaction of the substrate 105 is accelerated by the excitation energy 100a of the photosensitized redox agent in the excited state 106b, and as shown in FIG. 3C, at least a part of the product 107 of the substrate 105 is generated. . Typical examples of the product include a substance obtained by decomposing a substrate, a substance obtained by changing the structure of the substrate, or a substance obtained by dedoping a metal from a metal complex.

  The product 107 of the substrate 105 has a different conductivity than the substrate 105. Therefore, a voltage is applied to the first conductive layer and the second conductive layer, and the product 107 is generated, whereby the electric resistance of the memory element changes. Typically, an increase in resistance causing insulation or a decrease in resistance is given. That is, a voltage is applied to the first conductive layer 101 and the second conductive layer 103 to recombine electrons and holes in the light-emitting material, and the recombination energy is transferred to the photosensitized redox agent. . As a result, the photosensitized redox agent is in an excited state, the substrate is reacted with the excitation energy, and a product is generated, whereby the electric resistance of the memory element is changed and data can be written.

  Note that in the case of reading data from a memory element, data can be read by reading a difference between the electric resistance of the memory element before writing and the electric resistance of the memory element after writing.

    A memory element having a layer containing a light-emitting material, a photosensitized redox agent, and an organic compound having a substrate as shown in this embodiment can recombine electrons and holes in the light-emitting material. It is possible to control to do. For this reason, it is possible to increase the recombination probability of holes and electrons.

(Embodiment 4)
In this embodiment mode, the layer containing an organic compound as compared with Embodiment Mode 1 includes a first layer formed of a light-emitting material and a second layer formed of a substrate and a photosensitized redox agent. A memory element including the above will be described with reference to FIGS.

  The memory element of this embodiment mode includes a first conductive layer 101, a first layer 111 in contact with the first conductive layer, a second layer 112 in contact with the first layer 111, and a second layer 112. The second conductive layer 103 is in contact with the first conductive layer 103. Here, the first layer 111 is a layer formed of the light-emitting material 104, and the second layer 112 is a layer formed of the substrate 105 and the photosensitized redox agent 106a. The first conductive layer 101, the second conductive layer 103, the light-emitting material 104, the substrate 105, and the photosensitized redox agent 106a are formed using the same materials as in Embodiments 1 to 3. Can be formed.

  Here, a first layer 111 formed of a substrate 105 and a photosensitized redox agent 106a is formed between a first layer 111 formed of a light-emitting material 104 and a second conductive layer 103 functioning as a cathode. It has two layers 112. Therefore, the first layer 111 preferably functions as a hole transport / injection layer, and the second layer preferably functions as an electron transport / injection layer. Therefore, in this embodiment, the light-emitting material 104 is preferably formed using one or more materials selected from the hole-transporting material and the hole-injecting material described in Embodiment 3. The second layer functions as an electron transport / injection layer depending on the mixing ratio of the photosensitized redox agent and the substrate.

    Next, data writing in the memory element of this embodiment will be described. As shown in FIG. 4A, when a voltage is applied to the first conductive layer 101 and the second conductive layer 103 to generate a potential difference between the two conductive layers, holes and electrons are generated in the first layer 111. Recombination occurs to generate recombination energy 100b. By transferring the recombination energy to the photosensitized redox agent 106a, the photosensitized redox agent becomes an excited state 106b as shown in FIG. 4B. Note that when holes and electrons recombine in the first layer to emit light, the photosensitized redox agent 106a is excited by irradiating the photosensitized redox agent with light emission energy.

  Next, the reaction of the substrate 105 is promoted by the excitation energy 100a of the photosensitized redox agent in the excited state 106b, and a product 107 is generated as shown in FIG.

  The substrate product 107 has a different conductivity than the substrate 105. Therefore, by applying a voltage to the first conductive layer 101 and the second conductive layer 103 to generate the product 107, the electrical resistance of the memory element changes as in Embodiment Mode 1. Typically, an increase in resistance that causes insulation, a decrease in resistance, and the like can be given. That is, data can be written by a change in electrical resistance due to voltage application to the first conductive layer 101 and the second conductive layer 103.

  Note that in the case of reading data from a memory element, data can be read by reading a difference between an electric resistance of the memory element before writing and an electric resistance of the memory element after writing.

  Note that an electron-injecting layer 113 may be provided between the second conductive layer 103 and the second layer 112 as illustrated in FIG. The electron injection layer 113 can be formed using the electron injecting material described above.

Further, as shown in FIG. 5B, an electron injection layer 113 is provided between the second conductive layer 103 and the second layer 112, and between the first conductive layer 101 and the first layer 111. In addition, a hole injection layer 115 and a hole transport layer 114 may be provided. The hole injection layer 115 can be formed using the hole injecting material described above. The hole transport layer 114 can be formed using the hole transport material described above.

  As shown in FIG. 6A, the memory element includes a first conductive layer 101, a first layer 121 in contact with the first conductive layer, and a second layer 122 in contact with the first layer 121. Alternatively, the second conductive layer 103 in contact with the second layer 122 may be used. The second layer 122 is formed using the light-emitting material 104. The first conductive layer 101, the second conductive layer 103, the light-emitting material 104, the substrate 105, and the photosensitized redox agent 106a are formed using the same materials as in Embodiments 1 to 3. Is possible.

  Here, a second layer 122 formed of a light-emitting material 104 and a first conductive layer 101 functioning as an anode are formed of a substrate 105 and a photosensitized redox agent 106a. 1 layer 121 is provided. Therefore, the first layer 121 preferably functions as a hole transport / injection layer, and the second layer preferably functions as an electron transport / injection layer. Therefore, here, the light-emitting material 104 is preferably formed using one or more materials selected from the electron-transporting materials and the electron-injecting materials described in Embodiment 3. Note that the first layer 121 may include a light-emitting material. The second layer 122 functions as a hole transport / hole injection layer depending on the mixing ratio of the photosensitized redox agent and the substrate.

  Note that a hole-injection layer 115 may be provided between the first conductive layer 101 and the first layer 121 as illustrated in FIG. The hole injection layer 115 can be formed using the above-described hole injection material as appropriate.

  Further, as shown in FIG. 7B, a hole injection layer 115 is provided between the first conductive layer 101 and the first layer 121, and the second conductive layer 103 and the second layer 122 are provided. An electron transport layer 123 and an electron injection layer 113 may be provided therebetween. The electron injection layer 113 can be formed using the above-described electron injecting material as appropriate. The electron transport layer 123 can be formed using the electron transport material described above.

  A writing method and a reading method are the same as those of the memory element illustrated in FIGS. Specifically, as shown in FIGS. 6A and 7A, when a voltage is applied to the first conductive layer 101 and the second conductive layer 103 to generate a potential difference between the two conductive layers, Holes and electrons recombine in the second layer 122. By transferring the recombination energy to the photosensitized redox agent 106a of the first layer 121, as shown in FIGS. 6B and 7B, the photosensitized redox agent is in an excited state 106b. It becomes. Next, the reaction of the substrate 105 is accelerated by the excitation energy of the photosensitized redox agent in the excited state 106b, and a product 107 is generated as shown in FIGS. 6C and 7C.

  The substrate product 107 has a different conductivity than the substrate 105. Therefore, by applying a voltage to the first conductive layer 101 and the second conductive layer 103 to generate the product 107, the electrical resistance of the memory element changes as in Embodiment Mode 1. Typically, an increase in resistance that causes insulation, a decrease in resistance, and the like can be given. That is, data can be written by a change in electrical resistance due to voltage application to the first conductive layer 101 and the second conductive layer 103.

  Note that in the case of reading data from a memory element, data can be read by reading a difference between an electric resistance of the memory element before writing and an electric resistance of the memory element after writing.

  In addition, as illustrated in FIG. 8, the first conductive layer 101, the hole injection layer 115 in contact with the first conductive layer, the first layer 121 in contact with the hole injection layer 115, and the first layer 121 The second layer 124 in contact with the second layer 124, the third layer 125 in contact with the second layer 124, the electron injection layer 113 in contact with the third layer, and the second conductive layer 103 in contact with the electron injection layer 113. May be. Here, the first layer 121 is a layer on which the substrate 105 and the photosensitized redox agent 106a are formed, and functions as a hole transport / hole injection layer here. The second layer 124 is a layer formed using the light-emitting material 104. The third layer 125 is a layer formed of the substrate 105 and the photosensitized redox agent 106a, and functions as an electron transport / electron injection layer here.

  By laminating a layer formed of a material having a light-emitting property as in this embodiment and a layer having a substrate and a photosensitized redox agent, the layer having the substrate and the photosensitized redox agent can be used again. Holes or electrons that pass through without being bonded can be recombined in a layer formed using a light-emitting material. For this reason, it is possible to increase the recombination probability, and as a result, it is possible to facilitate writing to the storage element.

(Embodiment 5)
In this embodiment mode, a light-emitting element portion having a layer containing an organic compound formed of a light-emitting material, and a memory element portion having a layer containing an organic compound formed of a photosensitized redox agent and a substrate, Will be described with reference to FIGS. 10 and 11. FIG. In this embodiment mode, one of the electrodes of the light-emitting element portion and one of the electrodes of the memory element portion is used as a common electrode and is formed using a light-transmitting material so that light emitted from the light-emitting element is stored in the memory element. This photosensitized redox agent can be irradiated to bring the photosensitized redox agent into an excited state.

The memory element in this embodiment includes a first conductive layer 101, a first layer 142 in contact with the first conductive layer, a light-transmitting conductive layer 141 in contact with the first layer 142, The second layer 143 in contact with the conductive layer 141 having the property and the second conductive layer 103 in contact with the second layer 143 are formed. Here, the first conductive layer 101, the first layer 142 in contact with the first conductive layer, and the light-transmitting conductive layer 141 in contact with the first layer 142 function as a light-emitting element portion. The light-transmitting conductive layer 141, the second layer 143 in contact with the light-transmitting conductive layer 141, and the second conductive layer 103 in contact with the second layer 143 function as a memory element portion.

  The first layer 142 of the light-emitting element portion is a layer formed of the light-emitting material 104. Specifically, the hole injection layer 142a, the hole transport layer 142b, the light-emitting layer 142c, the electron transport layer 142d, It is preferable to form the electron injection layer 142e. With such a structure, when a voltage is applied to the first conductive layer 101 to the second conductive layer 103, recombination of electrons and holes occurs in the light-emitting layer 142c.

  The second layer 143 is a layer formed of the substrate 105 and the photosensitized redox agent 106a.

  The light-transmitting conductive layer 141 is formed using ITO, indium tin oxide containing silicon, indium oxide containing 2 to 20% zinc oxide (ZnO), or the like as appropriate. Further, titanium, molybdenum, tungsten, nickel, gold, platinum, silver, aluminum, lithium, magnesium, calcium, barium, and the like are thin and capable of transmitting light (typically 1 nm to 10 nm). It is formed using an alloy or the like.

  Next, data writing in the memory element of this embodiment will be described. As shown in FIG. 10A, when a voltage is applied to the first conductive layer 101 and the light-transmitting conductive layer 141 to generate a potential difference between the two conductive layers, holes and Electrons recombine, and the light-emitting material 104 emits light, generating light energy 100c.

  When light emitted from the light-emitting material 104 is irradiated onto the photosensitized redox agent 106a of the second layer 143, as shown in FIG. 10B, photosensitized redox is performed by the light energy. The agent 106a is in an excited state 106b.

  Next, the reaction of the substrate 105 is accelerated from 100a to the excitation energy of the photosensitized redox agent 106b, and as shown in FIG. 10C, a product 107 is generated.

  The substrate product 107 has a different conductivity than the substrate 105. Therefore, by applying a voltage to the first conductive layer 101 and the second conductive layer 103 to generate the product 107, the electrical resistance of the memory element changes as in Embodiment Mode 1. Typically, an increase in resistance that causes insulation, a decrease in resistance, and the like can be given. As described above, data can be written by a change in electrical resistance due to voltage application of the first conductive layer 101, the light-transmitting conductive layer 141, and the second conductive layer 103.

  Note that in the case of reading data from a memory element, data can be read by reading a difference between an electric resistance of the memory element before writing and an electric resistance of the memory element after writing.

11A, the memory element has a first conductive layer 101, a first layer 144 in contact with the first conductive layer, and a light-transmitting property in contact with the first layer 144. The conductive layer 141, the second layer 145 in contact with the light-transmitting conductive layer 141, and the second conductive layer 103 in contact with the second layer 145 may be used.

Here, the first conductive layer 101, the first layer 144 in contact with the first conductive layer, and the light-transmitting conductive layer 141 in contact with the first layer 144 function as a memory element portion. The light-transmitting conductive layer 141, the second layer 145 in contact with the light-transmitting conductive layer 141, and the second conductive layer 103 in contact with the second layer 145 function as a light-emitting element portion. Further, voltage need only be applied to the second conductive layer 103 and the light-transmitting conductive layer 141.

  The first layer 144 is a layer formed of the substrate 105 and the photosensitized redox agent 106a.

  The first layer 145 which is a part of the light-emitting element is a layer formed of the light-emitting material 104, specifically, a hole injection layer 145a, a hole transport layer 145b, a light-emitting layer 145c, and an electron transport. The layer 145d and the electron injection layer 145e are preferably formed. With such a structure, when a voltage is applied to the first conductive layer or the second conductive layer, recombination of electrons and holes occurs in the light-emitting layer 145c.

  A writing method and a reading method are the same as those of the memory element illustrated in FIGS. Specifically, as illustrated in FIG. 11A, voltage is applied to the first conductive layer 101, the light-transmitting conductive layer 141, and the second conductive layer 103, and a potential difference is generated between the two conductive layers. When generated, holes and electrons are recombined in the second layer 145, the light-emitting material 104 emits light, and light energy 100c is generated.

  When light emitted from the light-emitting material 104 is irradiated to the photosensitized redox agent 106a of the first layer 144, as shown in FIG. 11B, photosensitized redox is performed by the light energy. The agent 106a is in an excited state 106b.

  Next, the reaction of the substrate 105 is promoted by the excitation energy 100a of the photosensitized redox agent 106b, and as shown in FIG. 11C, a product 107 is generated.

  The substrate product 107 has a different conductivity than the substrate 105. Therefore, by applying a voltage to the first conductive layer 101 and the second conductive layer 103 to generate the product 107, the electrical resistance of the memory element changes as in Embodiment Mode 1. Typically, an increase in resistance that causes insulation, a decrease in resistance, and the like can be given. As described above, data can be written by a change in electrical resistance due to voltage application of the first conductive layer 101, the light-transmitting conductive layer 141, and the second conductive layer 103.

  Note that in the case of reading data from a memory element, data can be read by reading a difference between an electric resistance of the memory element before writing and an electric resistance of the memory element after writing.

  The memory element in this embodiment includes a light-emitting element portion including a layer containing an organic compound formed using a light-emitting material and a layer including an organic compound formed using a photosensitized redox agent and a substrate. The element portion is connected with a light-transmitting conductive layer which is a common electrode. Therefore, a voltage can be applied to each of the light emitting element portion and the memory element portion. Here, since it is sufficient to apply a voltage sufficient to emit light in the light emitting element portion, energy generated when holes and electrons recombine can be easily generated. Further, the light emitting element part does not contain a photosensitized redox agent and a substrate. Thus, data can be written to the memory element with a lower voltage than in the fourth embodiment. Furthermore, since it is possible to emit light by the memory element itself and write data using the light emission without providing a light irradiation device for writing to the outside, the memory device and the semiconductor device can be downsized and High integration is possible.

(Embodiment 6)
In the present embodiment, the second layer 143 formed of the substrate 105 and the photosensitized redox agent 106a shown in FIG. 10 of Embodiment 5 and the substrate 105 and the photosensitizer shown in FIG. 11 of Embodiment 5 are used. The first layer 144 formed of the oxidation / reduction agent 106a will be described.

  The memory element of this embodiment includes a first conductive layer 101, a first layer 142 in contact with the first conductive layer 101, a light-transmitting conductive layer 141 in contact with the first layer 142, A second layer 146 in contact with the light-conductive conductive layer 141 and a second conductive layer 103 in contact with the second layer 146 are formed. Here, the first layer 142 is a layer formed of the light-emitting material 104, and the second layer 143 is formed of the substrate 105, the photosensitized redox agent 106a, and the light-emitting material 147. Is the layer to be played.

  The first layer 142 is a layer formed of the light-emitting material 104 and has a structure similar to that in FIG.

  Next, data writing in the memory element of this embodiment will be described. As shown in FIG. 12A, voltage is applied to the first conductive layer 101, the light-transmitting conductive layer 141, and the second conductive layer 103, so that the first conductive layer 101 and the light-transmitting property are changed. When a potential difference is generated between the conductive layers 141 and the light-transmitting conductive layer 141 and the second conductive layer 103, holes and electrons are recombined in the light-emitting material 104 of the first layer 142. In addition, the light-emitting material 104 emits light, and also in the light-emitting material 147 of the second layer 146, holes and electrons are recombined to emit light, generating light energy 100c.

  When light emitted from the light-emitting materials 104 and 147 is irradiated onto the photosensitized redox agent 106a of the second layer 146, as shown in FIG. The redox agent 106a is in an excited state 106b and has an excitation energy 100a. Note that in the case where the light-emitting material 147 and the photosensitized redox agent 106a are in contact with each other, the recombination energy is transferred to the photosensitized redox agent 106a even if the light-emitting material 147 does not emit light.

  Next, the reaction of the substrate 105 is promoted by the excitation energy 100a of the photosensitized redox agent in the excited state 106b, and a product 107 is generated as shown in FIG.

  The substrate product 107 has a different conductivity than the substrate 105. Therefore, voltage is applied to the first conductive layer and the second conductive layer, and the product 107 is generated, so that the electrical resistance of the memory element changes as in the first embodiment. Typically, an increase in resistance that causes insulation, a decrease in resistance, and the like can be given. As described above, data can be written by a change in electrical resistance due to voltage application of the first conductive layer 101, the light-transmitting conductive layer 141, and the second conductive layer 103.

  Note that when data in a memory element is read, the data can be read by reading a difference in electric resistance between the memory elements.

  13A, the first conductive layer 101, the first layer 148 in contact with the first conductive layer 101, and the light-transmitting conductive layer 141 in contact with the first layer 148 are used. And the second layer 145 in contact with the light-transmitting conductive layer 141 and the second conductive layer 103 in contact with the second layer 145. Here, the first layer 148 is a layer formed of the substrate 105, the photosensitized redox agent 106a, and the light-emitting material 149. Further, the second layer 145 is a layer formed using the light-emitting material 104.

  A writing method and a reading method are the same as those of the memory element illustrated in FIGS. Specifically, a voltage is applied to the first conductive layer 101, the light-transmitting conductive layer 141, and the second conductive layer 103 as illustrated in FIG. When a potential difference is generated between the light-transmitting conductive layer 141 and the light-transmitting conductive layer 141 and the second conductive layer 103, holes in the light-emitting material 104 of the second layer 145 are formed. The electrons 104 recombine and the light-emitting material 104 emits light, and the light-emitting material 147 of the first layer 148 also recombines holes and electrons to emit light, generating light energy 100c.

  When light emitted from the light-emitting materials 104 and 147 is applied to the photosensitized oxidation / reduction agent 106a of the first layer 148, as shown in FIG. The redox agent 106a is in an excited state 106b and has an excitation energy 100a. Note that in the case where the light-emitting material 147 and the photosensitized redox agent 106a are in contact with each other, the recombination energy is transferred to the photosensitized redox agent 106a even if the light-emitting material 147 does not emit light.

  Next, the reaction of the substrate 105 is accelerated by the excitation energy of the photosensitized redox agent in the excited state 106b, and a product 107 is generated as shown in FIG.

  The substrate product 107 has a different conductivity than the substrate 105. Therefore, voltage is applied to the first conductive layer and the second conductive layer, and the product 107 is generated, so that the electrical resistance of the memory element changes as in the first embodiment. Typically, an increase in resistance that causes insulation, a decrease in resistance, and the like can be given. As described above, data can be written by a change in electrical resistance due to voltage application of the first conductive layer 101, the light-transmitting conductive layer 141, and the second conductive layer 103.

  Note that when data in a memory element is read, the data can be read by reading a difference in electric resistance between the memory elements.

  The memory element in this embodiment includes a light-emitting element portion including a layer containing an organic compound formed using a light-emitting material and a layer including an organic compound formed using a photosensitized redox agent and a substrate. The element portion is connected with a light-transmitting conductive layer which is a common electrode. In addition, the layer formed of the substrate of the memory element portion and the layer formed of the photosensitized redox agent also has a material having a light-emitting property, and the recombination energy generated by recombination in the layer having the light-emitting property is also light. Move to sensitized redox agent 106a. Therefore, it is possible to bring the photosensitized redox agent into an excited state with more recombination energy. As a result, data can be written at a low voltage and the writing success rate can be increased. It is. Furthermore, since it is possible to emit light by the memory element itself and write data using the light emission without providing a light irradiation device for writing to the outside, the memory device and the semiconductor device can be downsized and High integration is possible.

(Embodiment 7)
In the memory element described in any of Embodiments 1 to 6, a charge transport layer formed of an inorganic compound and an organic compound may be provided between the first conductive layer and the layer containing an organic compound. Further, a charge transport layer formed of an inorganic compound and an organic compound may be provided between the second conductive layer and the layer containing an organic compound. Furthermore, a charge transport layer formed of an inorganic compound and an organic compound is provided between the first conductive layer and the layer containing an organic compound, and between the second conductive layer and the layer containing an organic compound. May be. Note that although description is made here with use of Embodiment 1, the present invention can be appropriately applied to Embodiments 2 to 6.

  The memory element illustrated in FIG. 9A includes a hole-transport layer 151 between the first conductive layer 101 serving as an anode and the layer 102 containing an organic compound. The hole transport layer 151 includes an organic compound and an inorganic compound having an electron accepting property with respect to the organic compound. By mixing an organic compound with an electron-accepting inorganic compound, many holes are generated in the organic compound, and extremely excellent hole injection / transport properties are exhibited.

Since holes are generated in the organic compound, the organic compound is formed using the above-described hole-transporting organic compound as appropriate. The inorganic compound may be anything as long as it can easily receive electrons from the organic compound, and various metal oxides or metal nitrides can be used. Such transition metal oxides are preferable because they easily exhibit electron accepting properties. Specific examples include titanium oxide, zirconium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, and zinc oxide. Among the metal oxides described above, any of the transition metal oxides in Groups 4 to 8 of the periodic table has a high electron accepting property and is a preferred group. Vanadium oxide, molybdenum oxide, tungsten oxide, and rhenium oxide are particularly preferable because they can be vacuum-deposited and are easy to handle.

  The memory element illustrated in FIG. 9B includes an electron-transport layer 152 between the second conductive layer 103 serving as a cathode and the layer 102 containing an organic compound. The electron transport layer 152 includes an organic compound and an inorganic compound having an electron donating property with respect to the organic compound. By mixing an organic compound with an inorganic compound having an electron donating property, a large number of electrons are generated in the organic compound, and extremely excellent electron injecting / transporting properties are exhibited.

Since electrons are generated in the organic compound, the organic compound is formed using the above-described electron-transporting organic compound as appropriate. The inorganic compound may be anything as long as it easily gives electrons from an organic compound, and various metal oxides or metal nitrides can be used. Alkali metal oxides, alkaline earth metal oxides can be used. Rare earth metal oxides, alkali metal nitrides, alkaline earth metal nitrides, and rare earth metal nitrides are preferred because they easily exhibit electron donating properties. Specific examples include lithium oxide, strontium oxide, barium oxide, erbium oxide, lithium nitride, magnesium nitride, calcium nitride, yttrium nitride, and lanthanum nitride. In particular, lithium oxide, barium oxide, lithium nitride, magnesium nitride, and calcium nitride are preferable because they can be vacuum-deposited and are easy to handle.

  The memory element illustrated in FIG. 9C has a hole transport layer 151 between the first conductive layer 101 serving as an anode and the layer 102 containing an organic compound, and the second conductive layer 103 serving as a cathode. And the layer 102 containing an organic compound have an electron transport layer 152.

Note that a hole transport layer may be formed between the hole transport layer 151 and the layer 102 containing an organic compound by using the above-described organic compound having a hole transport property. Further, an electron transport layer may be formed using the above-described organic compound having an electron transport property between the electron transport layer 152 and the layer 102 containing an organic compound.

  As described above, by providing a charge transport layer formed using an organic compound and an inorganic compound between a conductive layer and a layer containing an organic compound, excellent conductivity can be obtained in the memory element. Therefore, recombination of electrons and holes can be performed at a lower voltage than before, and data can be written with low power consumption.

(Embodiment 8)
In this embodiment, a structural example of a memory device including the memory element of the above embodiment will be described with reference to drawings. More specifically, the case where the structure of the memory device is a passive matrix type will be described.

  FIG. 14A shows a configuration example of the memory device of this embodiment, which includes a memory cell array 22 in which memory cells 21 are provided in a matrix, a column decoder 26a, a read circuit 26b, and a selector 26c. It has a bit line drive circuit 26, a word line drive circuit 24 having a row decoder 24a and a level shifter 24b, an interface 23 having a write circuit and the like for performing exchanges with the outside. Note that the structure of the memory device 16 shown here is merely an example, and other circuits such as a sense amplifier, an output circuit, and a buffer may be included, and a write circuit may be provided in the bit line driver circuit.

  The memory cell 21 includes a first conductive layer constituting the bit line Bx (1 ≦ x ≦ m), a second conductive layer constituting the word line Wy (1 ≦ y ≦ n), and a layer containing an organic compound And have. The layer containing an organic compound is provided as a single layer or a stacked layer between the first conductive layer and the second conductive layer.

  An example of a top surface structure and a cross-sectional structure of the memory cell array 22 is shown in FIG. 15A shows the top structure of the memory cell array 22, and the cross-sectional structure between A and B in FIG. 15A corresponds to FIGS. 15B and 15C, and FIG. ) Corresponds to FIG. 15D. Note that the insulating layer 27 functioning as a protective film is omitted in FIG.

Memory cells 21 are provided in a matrix in the memory cell array 22 (see FIG. 15A). The memory cell 21 includes a memory element 80 (see FIG. 15B). The memory element 80 includes a first conductive layer 31 extending in the first direction on the substrate 30, a layer 29 containing an organic compound covering the first conductive layer 31, and the first direction intersecting with the first direction at 90 degrees. And a second conductive layer 28 extending in the second direction. Here, an insulating layer 27 that functions as a protective film is provided so as to cover the second conductive layer 28.

The memory elements described in Embodiments 1 to 7 can be used as appropriate for the memory element 80.

  In the memory element, a rectifying element may be provided on the side opposite to the layer 29 containing an organic compound with the first conductive layer 31 interposed therebetween. The element having a rectifying property is a transistor, a diode, or the like in which a gate electrode and a drain electrode are connected. Typical examples of the diode include a PN junction diode, a diode having a PIN junction, an avalanche diode, and the like. Moreover, you may use the diode of another structure. Note that a rectifying element may be provided on the side opposite to the layer containing an organic compound through the second conductive layer. Further, the element having a rectifying property may be provided between the layer 29 containing an organic compound and the first conductive layer 31. Further, a rectifying element may be provided between the layer 29 containing an organic compound and the second conductive layer 28. As described above, by providing a rectifying element, current flows only in one direction, so that a read error is reduced and a read margin is improved.

  Further, a thin film transistor (TFT) may be provided over an insulating substrate and the memory element 80 may be provided thereover, or a semiconductor substrate such as Si or an SOI substrate may be used instead of the insulating substrate. Alternatively, a field effect transistor (FET) may be formed and a memory element 80 may be provided thereon. In addition, since a transistor formed using a single crystal semiconductor can be finely processed, high integration can be achieved and the semiconductor device can be miniaturized. In addition, since it is formed of a single crystal semiconductor, high-speed operation is possible. Note that although the example in which the memory element is formed over a thin film transistor or a field effect transistor is described here, the memory element may be provided by bonding the thin film transistor or the field effect transistor. In this case, the memory element portion and the thin film transistor or the field effect transistor can be provided by being manufactured in separate steps and then bonded together using a conductive film, an anisotropic conductive adhesive, or the like. Further, any configuration of the thin film transistor or the field effect transistor may be used as long as it is a known one.

  In addition, when there is a concern about the influence of the electric field in the lateral direction between adjacent memory elements, the organic compound provided in each memory element is separated to separate the layer containing the organic compound provided in each memory element. A partition wall (insulating layer) may be provided between the layers containing. That is, a structure in which a layer containing an organic compound is selectively provided for each memory cell may be employed.

  Further, when the layer 29 containing an organic compound is provided so as to cover the first conductive layer 31, the step of the layer 29 containing the organic compound caused by the step of the first conductive layer 31 and the horizontal direction between the memory cells are performed. In order to prevent the influence of the electric field, a partition wall (insulating layer) 39 may be provided between the first conductive layers 31 (FIG. 15C). Note that in the cross section of the partition wall (insulating layer) 39, the side surface of the partition wall (insulating layer) 39 is inclined at an angle of 10 ° to less than 60 °, preferably 25 ° to 45 ° with respect to the surface of the first conductive layer 31. It is preferable to have an angle. Furthermore, it is preferable that it is curved. Thereafter, an insulating layer 32, a layer 29 containing an organic compound, and a second conductive layer 28 are formed so as to cover the first conductive layer 31 and the partition wall (insulating layer) 39.

Further, instead of the partition wall (insulating layer) 39, an interlayer insulating layer 40a covering a part of the first conductive layer 31 extending in the first direction on the substrate 30, and a partition wall provided on the interlayer insulating layer (Insulating layer) 40b may be provided (FIG. 15D).

The interlayer insulating layer 40 a covering a part of the first conductive layer 31 has an opening for each memory element 80. The partition (insulating layer) 40b is provided in a region where no opening is formed in the interlayer insulating layer. Further, the partition wall (insulating layer) 40 b extends in the second direction similarly to the second conductive layer 28. Further, the partition wall (insulating layer) 40b has an inclination angle of 95 ° to 135 ° with respect to the surface of the interlayer insulating layer 40a.

The partition wall (insulating layer) 40b is formed by using a positive photosensitive resin in which an unexposed portion remains, and adjusting the exposure amount or the development time so that the lower part of the pattern is etched more in accordance with a photolithography method. The height of the partition wall (insulating layer) 40b is set to be larger than the thickness of the layer 29 containing the organic compound and the second conductive layer 28. As a result, the first conductive layer 31 is separated into a plurality of electrically independent regions only by the process of depositing the layer 29 containing the organic compound and the second conductive layer 28 on the entire surface of the substrate 30 on the substrate 30. A layer 29 containing a stripe-shaped organic compound and a second conductive layer 28 extending in a direction crossing the first direction can be formed. For this reason, the number of processes can be reduced. Note that the layer 29a and the conductive layer 28a containing an organic compound are also formed over the partition wall (insulating layer) 40b, but the layer 29 and the conductive layer 28 containing an organic compound are separated from each other.

  Next, an operation when data is written to the storage device will be described. Here, a case where data is written by voltage application will be described (see FIGS. 14 and 15).

  When data is written by applying a voltage, one memory cell 21 is selected by the row decoder 24a, the column decoder 26a, and the selector 26c, and then the data is written to the memory cell 21 using a write circuit. (See FIG. 14A). When a voltage is applied between the first conductive layer 31 and the second conductive layer 28 of the memory cell, a layer formed of a light emitting material emits light. The photosensitized redox agent in the layer containing the organic compound is excited by the emission energy. In addition, the substrate undergoes a chemical reaction by the excited photosensitized redox agent to generate a chemical product. As a result, the electrical resistance of the memory element changes.

  The electric resistance of the memory element having the reaction product changes as compared with the memory element before writing. As described above, data is written by applying a change in electric resistance between two conductive layers by applying a voltage. For example, when a layer including an organic compound to which no voltage is applied is set to “0” data, a large voltage is selectively applied to the layer including the organic compound of a desired memory element when writing “1” data. Apply to change resistance.

Next, an operation when data is read from the organic memory will be described (FIG. 14B). In reading data, the electrical characteristics between the first conductive layer and the second conductive layer constituting the memory cell are different between the memory cell having data “0” and the memory cell having data “1”. Use it. For example, the effective electrical resistance between the first conductive layer and the second conductive layer constituting the memory cell having data “0” (hereinafter simply referred to as the electrical resistance of the memory cell) is R0 at the read voltage. A method of reading data by using the difference in electric resistance when the electric resistance of the memory cell having data “1” is R1 in the read voltage will be described. Note that R1 <R0. Here, the read circuit 26b includes a resistance element 46 and a sense amplifier 47. The resistance element 46 has a resistance value Rr, and R1 <Rr <R0. However, the configuration of the readout circuit 26b is not limited to the above configuration, and may have any configuration. For example, a transistor 48 may be used instead of the resistance element 46, and a clocked inverter 49 may be used instead of the sense amplifier 47 (FIG. 14C). The clocked inverter 49 receives a signal φ or an inverted signal φ that is High when reading is performed and is Low when the reading is not performed.

  In reading data, the memory cell 21 is selected by the row decoder 24a, the column decoder 26a, and the selector 26c. Specifically, a predetermined voltage Vy is applied to the word line Wy connected to the memory cell 21 by the row decoder 24a. Further, the bit line Bx connected to the memory cell 21 is connected to the terminal P of the read 26b by the column decoder 26a and the selector 26c. As a result, the potential Vp of the terminal P becomes a value determined by resistance division by the resistance element 46 (resistance value Rr) and the memory cell 21 (resistance value R0 or R1). Therefore, when the memory cell 21 has data “0”, Vp0 = Vy + (V0−Vy) × R0 / (R0 + Rr). When the memory cell 21 has data “1”, Vp1 = Vy + (V0−Vy) × R1 / (R1 + Rr). As a result, in FIG. 14A, Vref is selected to be between Vp0 and Vp1, and in FIG. 14B, the change point of the clocked inverter is selected to be between Vp0 and Vp1. Thus, Low / High (or High / Low) is output as the output potential Vout according to the data “0” / “1”, and reading can be performed.

  For example, the sense amplifier 47 is operated at Vdd = 3V, and Vy = 0V, V0 = 3V, and Vref = 1.5V. If R0 / Rr = Rr / R1 = 9, if the memory cell data is “0”, Vp0 = 2.7 V and High is output as Vout, and if the memory cell data is “1”, Vp1 = 0.3V, and Low is output as Vout. Thus, the memory cell can be read.

Note that when data is read, a forward voltage is applied. Further, a reverse voltage may be applied.

  According to the above method, the state of the electrical resistance of the layer 29 containing an organic compound is read as a voltage value by utilizing the difference in resistance value and resistance division. However, a method of comparing current values may be used. This is because, for example, the current value Ia1 when no voltage is applied to the layer containing the organic compound and the resistance value Ib1 when the voltage is applied and the two conductive films are short-circuited satisfy Ia1 <Ib1. To do.

In this embodiment mode, the resistance value of the memory element is replaced with the magnitude of the voltage, but the present invention can be implemented without being limited to this. For example, in addition to using a difference in electrical resistance, reading may be performed using a difference in current value. In addition, when the electrical characteristics of the memory cell have data “0” and “1” and diode characteristics with different threshold voltages, reading may be performed using the threshold voltage difference. Furthermore, a method of precharging the bit line can be employed.

(Embodiment 9)
In this embodiment, a memory device having a structure different from that in Embodiment 8 is described. Specifically, a case where the structure of the memory device is an active matrix type will be described.

  FIG. 16A illustrates an example of a structure of the memory device described in this embodiment. A memory cell array 222 in which memory cells 221 are provided in a matrix, a column decoder 226a, a reading circuit 226b, and a selector 226c are included. A bit line driving circuit 226 having a row decoder 224a and a word line driving circuit 224 having a level shifter 224b, an interface 223 having a writing circuit and the like and performing exchange with the outside. Note that the structure of the memory device 216 shown here is merely an example, and other circuits such as a sense amplifier, an output circuit, and a buffer may be included, and a write circuit may be provided in the bit line driver circuit.

  The memory cell 221 includes a first wiring that forms a bit line Bx (1 ≦ x ≦ m), a second wiring that forms a word line Wy (1 ≦ y ≦ n), a transistor 240, and a storage element 241. And have. The memory element 241 has a structure in which a layer containing an organic compound is sandwiched between a pair of conductive layers.

  Next, an example of a top view and a cross-sectional view of the memory cell array 222 having the above structure is described with reference to FIGS. Note that FIG. 17A illustrates an example of a top view of the memory cell array 222, and FIG. 17B illustrates a cross-sectional view taken along a line AB in FIG. Note that in FIG. 17A, the partition (insulating layer) 249, the layer 244 containing an organic compound, and the second conductive layer 245 which are formed over the first conductive layer 243 are omitted.

  In the memory cell array 222, a plurality of memory cells 221 are provided in a matrix. In addition, the memory cell 221 includes a transistor 240 functioning as a switching element over a substrate 230 having an insulating surface and a memory element 241 connected to the transistor 240 (FIGS. 17A and 17B). )reference.). The memory element 241 includes a first conductive layer 243 formed over the insulating layer 248, a layer 244 containing an organic compound that covers the first conductive layer 243 and the partition wall (insulating layer) 249, and a second conductive layer 245. And have. Note that a partition wall (insulating layer) 249 that covers part of the first conductive layer is formed. A thin film transistor is used as the transistor 240. In addition, the insulating layer 236 which covers the second conductive layer 245 and functions as a protective film is provided.

  One embodiment of a thin film transistor that can be used for the transistor 240 is described with reference to FIGS. FIG. 25A illustrates an example in which a top-gate thin film transistor is applied. An insulating layer 205 is provided over a substrate 230 having an insulating surface, and a thin film transistor is provided over the insulating layer 205. In the thin film transistor, a semiconductor layer 1302 and an insulating layer 1303 which can function as a gate insulating layer are provided over the insulating layer 205. Over the insulating layer 1303, a gate electrode 1304 is formed corresponding to the semiconductor layer 1302, and an insulating layer 1305 functioning as a protective layer and an insulating layer 248 functioning as an interlayer insulating layer are provided thereover. In addition, a first conductive layer 243 connected to each of the source region and the drain region of the semiconductor layer is formed. Further, an insulating layer functioning as a protective layer may be formed thereon.

  The semiconductor layer 1302 is a layer formed of a semiconductor having a crystal structure, and a non-single-crystal semiconductor or a single-crystal semiconductor can be used. In particular, an amorphous or microcrystalline semiconductor is crystallized by crystallizing a semiconductor that is crystallized by laser light irradiation, a crystallized semiconductor that is crystallized by heat treatment, or a combination of heat treatment and laser light irradiation. It is preferable to apply a crystalline semiconductor. In the heat treatment, a crystallization method using a metal element such as nickel which has an action of promoting crystallization of a silicon semiconductor can be applied.

In the case of crystallization by irradiating with laser light, high repetition frequency with continuous wave laser light irradiation or repetition frequency of 10 MHz or more and pulse width of 1 nanosecond or less, preferably 1 to 100 picoseconds. By irradiating with ultrashort pulse light, crystallization can be performed while continuously moving the molten zone in which the crystalline semiconductor is melted in the irradiation direction of the laser light. By such a crystallization method, a crystalline semiconductor having a large particle diameter and a crystal grain boundary extending in one direction can be obtained. By adjusting the carrier drift direction to the direction in which the crystal grain boundary extends, the field-effect mobility in the transistor can be increased. For example, 400 cm ² / V · sec or more can be realized.

When the crystallization process is performed using a crystallization process at a heat resistant temperature (about 600 ° C.) or lower of the glass substrate, a large-area glass substrate can be used. Therefore, a large amount of semiconductor devices can be manufactured per substrate, and the cost can be reduced.

Alternatively, the semiconductor layer 1302 may be formed by performing a crystallization step by heating at a temperature equal to or higher than the heat resistant temperature of the glass substrate. Typically, a quartz substrate is used as the insulating substrate, and the semiconductor layer 1302 is formed by heating an amorphous or microcrystalline semiconductor at 700 ° C. or higher. As a result, a semiconductor with high crystallinity can be formed. Therefore, a thin film transistor that has favorable characteristics such as response speed and mobility and can operate at high speed can be provided.

  The gate electrode 1304 can be formed using a metal or a polycrystalline semiconductor to which an impurity of one conductivity type is added. In the case of using a metal, tungsten (W), molybdenum (Mo), titanium (Ti), tantalum (Ta), aluminum (Al), or the like can be used. Moreover, the metal nitride which nitrided the metal mentioned above can be used. Or it is good also as a structure which laminated | stacked the 1st layer which consists of the said metal nitride, and the 2nd layer which consists of the said metal. In the case of a laminated structure, the end of the first layer may protrude outward from the end of the second layer. At this time, a barrier metal can be formed by using a metal nitride for the first layer. That is, the second layer metal can be prevented from diffusing into the insulating layer 1303 and the semiconductor layer 1302 below the insulating layer 1303.

Sidewalls (sidewall spacers) 1308 are formed on the side surfaces of the gate electrode 1304. The sidewall can be formed by forming an insulating layer made of silicon oxide on the substrate by a CVD method and anisotropically etching the insulating layer by a RIE (Reactive ion etching) method.

  Various structures such as a single drain structure, an LDD (lightly doped drain) structure, and a gate overlap drain structure can be applied to a transistor including the semiconductor layer 1302, the insulating layer 1303, the gate electrode 1304, and the like. Here, a thin film transistor having an LDD structure in which a low concentration impurity region 1310 is formed in a semiconductor layer where sidewalls overlap is shown. It is also possible to apply a single gate structure, equivalently a multi-gate structure in which transistors to which a gate voltage of the same potential is applied are connected in series, or a dual gate structure in which a semiconductor layer is sandwiched between gate electrodes. it can.

  The insulating layer 248 is formed using an inorganic insulating material such as silicon oxide or silicon oxynitride, or an organic insulating material such as an acrylic resin or a polyimide resin. When a coating method such as spin coating or roll coater is used, the insulating layer can be formed by heat treatment after coating an insulating film material dissolved in an organic solvent. For example, a film containing a siloxane bond can be formed by coating, and the insulating layer can be formed by heat treatment at 200 to 400 degrees. By forming the insulating layer 248 by an application method or an insulating layer flattened by reflow, disconnection of wiring formed on the layer can be prevented. It can also be used effectively when forming multilayer wiring.

  The first 243 formed over the insulating layer 248 can be provided so as to intersect with a wiring formed in the same layer as the gate electrode 1304, and forms a multilayer wiring structure. A multilayer wiring structure can be formed by stacking a plurality of insulating layers having the same function as the insulating layer 248 and forming wirings on the insulating layers. The conductive layer 243 functioning as a wiring includes a low resistance material such as aluminum (Al) such as a stacked structure of titanium (Ti) and aluminum (Al), a stacked structure of molybdenum (Mo) and aluminum (Al), and titanium ( It is preferably formed in combination with a barrier metal using a refractory metal material such as Ti) or molybdenum (Mo).

  FIG. 25B illustrates an example in which a bottom-gate thin film transistor is applied. An insulating layer 205 is formed over a substrate 230 having an insulating surface, and a thin film transistor is provided thereover. The thin film transistor is provided with a gate electrode 1304, an insulating layer 1303 functioning as a gate insulating layer, a semiconductor layer 1302, a channel protective layer 1309, an insulating layer 1305 functioning as a protective layer, and an insulating layer 248 functioning as an interlayer insulating layer. . Further, an insulating layer functioning as a protective layer may be formed thereon. The conductive layer 243 functioning as a wiring can be formed over the insulating layer 1305 or the insulating layer 248. Note that in the case of a bottom-gate thin film transistor, the insulating layer 205 is not necessarily formed.

In the case where the substrate 230 having an insulating surface is a flexible substrate, the heat resistant temperature is lower than that of a non-flexible substrate such as a glass substrate. For this reason, the thin film transistor is preferably formed using an organic semiconductor.

Here, a structure of a thin film transistor using an organic semiconductor is described with reference to FIGS. FIG. 25C illustrates an example of applying a staggered organic semiconductor transistor. An organic semiconductor transistor is provided over a flexible substrate 1401. The organic semiconductor transistor includes a gate electrode 1402, an insulating layer 1403 functioning as a gate insulating film, a semiconductor layer 1404 overlapping with the insulating layer functioning as the gate electrode and the gate insulating film, and a conductive layer 243 functioning as a wiring connected to the semiconductor layer 1404. Is formed. Note that the semiconductor layer is in contact with the insulating layer 1403 functioning as a gate insulating film and the conductive layer 243 functioning as a wiring.

The gate electrode 1402 can be formed using a material and a method similar to those of the gate electrode 1304. Alternatively, the gate electrode 1402 can be formed by drying and baking using a droplet discharge method. Alternatively, the gate electrode 1402 can be formed by printing a paste containing fine particles over a flexible substrate by a printing method, followed by drying and baking. As typical examples of the fine particles, fine particles mainly containing any of gold, copper, an alloy of gold and silver, an alloy of gold and copper, an alloy of silver and copper, and an alloy of gold, silver, and copper may be used. Further, fine particles mainly containing a conductive oxide such as indium tin oxide (ITO) may be used.

The insulating layer 1403 functioning as a gate insulating film can be formed using a material and a method similar to those of the insulating layer 1303. However, when an insulating layer is formed by heat treatment after applying an insulating film material dissolved in an organic solvent, the heat treatment temperature is lower than the heat resistance temperature of the flexible substrate.

Examples of the material of the semiconductor layer 1404 of the organic semiconductor transistor include polycyclic aromatic compounds, conjugated double bond compounds, phthalocyanines, and charge transfer complexes. For example, anthracene, tetracene, pentacene, 6T (hexathiophene), TCNQ (tetracyanoquinodimethane), PTCDA (perylene carboxylic acid anhydride), NTCDA (naphthalene carboxylic acid anhydride) and the like can be used. Examples of the material for the semiconductor layer 1404 of the organic semiconductor transistor include π-conjugated polymers such as organic polymer compounds, carbon nanotubes, polyvinyl pyridine, and phthalocyanine metal complexes. In particular, when a polyacetylene, polyaniline, polypyrrole, polythienylene, polythiophene derivative, poly (3 alkylthiophene), polyparaphenylene derivative or polyparaphenylene vinylene derivative is used, which is a π-conjugated polymer whose skeleton is composed of conjugated double bonds preferable.

  As a method for forming the semiconductor layer of the organic semiconductor transistor, a method capable of forming a film with a uniform thickness on the substrate may be used. The thickness is 1 nm to 1000 nm, preferably 10 nm to 100 nm. As a specific method, an evaporation method, a coating method, a spin coating method, a solution casting method, a dipping method, a screen printing method, a roll coater method, or a droplet discharge method can be used.

FIG. 25D illustrates an example in which a coplanar organic semiconductor transistor is used. An organic semiconductor transistor is provided over a flexible substrate 1401. In the organic semiconductor transistor, a gate electrode 1402, an insulating layer 1403 functioning as a gate insulating film, a conductive layer 243 functioning as a wiring, and a semiconductor layer 1404 overlapping with the insulating layer functioning as a gate electrode and a gate insulating layer are formed. The conductive layer 243 functioning as a wiring is in contact with the insulating layer and the semiconductor layer functioning as a gate insulating layer.

Further, the thin film transistor and the organic semiconductor transistor may be provided in any configuration as long as they can function as a switching element.

  Alternatively, a transistor may be formed using a single crystal substrate or an SOI substrate, and a memory element may be provided thereover. The SOI substrate may be formed using a method called wafer bonding or a method called SIMOX in which an insulating layer is formed inside by implanting oxygen ions into the Si substrate. Here, as shown in FIG. 17C, a memory element 241 is connected to a field-effect transistor 262 provided over a single crystal semiconductor substrate 260. In addition, an insulating layer 250 is provided so as to cover the wiring of the field-effect transistor 262, and the memory element 241 is provided over the insulating layer 250.

Since a transistor formed using such a single crystal semiconductor has favorable characteristics such as response speed and mobility, a transistor that can operate at high speed can be provided. In addition, since the transistor has less variation in characteristics, a semiconductor device that achieves high reliability can be provided.

The memory element 241 includes a first conductive layer 264 formed over the insulating layer 250, a layer 244 containing an organic compound that covers the first conductive layer 243 and the partition wall (insulating layer) 249, and a second conductive layer 245. And have. Note that a partition wall (insulating layer) 249 that covers part of the first conductive layer is formed.

  In this manner, the first conductive layer 264 can be freely arranged by providing the insulating layer 250 and forming the memory element 241. In other words, in the structures of FIGS. 17A and 17B, the memory element 241 needs to be provided in a region where the wiring of the transistor 240 is avoided; however, with the above structure, for example, the layer 251 including the transistor The memory element 241 can be formed above the provided field effect transistor 262. As a result, the storage device 216 can be more highly integrated.

  Note that in the structure illustrated in FIGS. 17B and 17C, the layer 244 including an organic compound is provided over the entire surface of the substrate; however, the layer 244 including an organic compound is selectively provided only in each memory cell. It may be provided. In this case, the use efficiency of the material can be improved by providing a layer containing the organic compound selectively by discharging and baking the organic compound using a droplet discharge method or the like.

  The materials and formation methods of the first conductive layers 243 and 264 and the second conductive layer 245 can be similarly performed using any of the materials and formation methods described in Embodiment Mode 1.

  The layer 244 containing an organic compound can be provided using a material and a formation method similar to those of the layer 29 containing an organic compound described in Embodiment Mode 1.

  Further, a rectifying element may be provided between the first conductive layers 243 and 264 and the layer 244 containing an organic compound. The element having a rectifying property is a transistor or a diode in which a gate electrode and a drain electrode are connected. Note that the element having a rectifying property may be provided between the layer 244 containing an organic compound and the second conductive layer 245.

Further, after a separation layer is provided over the substrate 230 having an insulating surface and the transistor 253 and the memory element 241 are formed over the separation layer, the transistor 253 and the memory element 241 are separated from the separation layer. A layer 253 including a transistor and the memory element 241 may be attached to the memory element 241 with an adhesive layer 462 interposed therebetween (see FIG. 20). Note that as a peeling method, (1) a metal oxide layer is provided as a peeling layer between a substrate having an insulating surface and a layer having a transistor, the metal oxide layer is weakened by crystallization, and the physical oxide is used for the peeling. (2) An amorphous silicon film containing hydrogen is provided as a separation layer between a substrate having an insulating surface and a layer having a transistor, and the amorphous silicon film is irradiated with laser light. A method of releasing hydrogen gas to release a substrate having high heat resistance, or a method of peeling an amorphous silicon film in a peeling layer and removing the amorphous silicon film to peel off the layer having the transistor, (3) mechanically remove substrate having high heat resistance which is formed with a layer having a transistor, or a solution or NF _3, BrF _3, be removed by etching with halogen fluoride gas such as ClF ₃ (4) A metal layer and a metal oxide layer are provided as a separation layer between a substrate having an insulating surface and a layer having a transistor, the metal oxide layer is weakened by crystallization, and a part of the metal layer is a solution. Alternatively, a method of physically peeling off the weakened metal oxide layer after etching with a halogen fluoride gas such as NF ₃ , BrF ₃ , or ClF ₃ may be used.

  Further, as the substrate 461, a flexible substrate shown in the substrate 30 shown in Embodiment Mode 1, a film having a thermoplastic resin layer, paper made of a fibrous material, or the like can be used, so that the memory device can be downsized. It is possible to reduce the thickness and weight.

  Next, an operation when data is written to the storage device 216 will be described (FIG. 16).

  When data is written by applying a voltage, one memory cell 221 is selected by the row decoder 224a, the column decoder 226a, and the selector 226c, and then data is written to the memory cell 221 by using a write circuit. (See FIG. 16A). When a voltage is applied between the first conductive layer 243 and the second conductive layer 245 of the memory cell, a layer formed using a light-emitting material emits light. The photosensitized redox agent in the layer containing the organic compound is excited by the emission energy. In addition, the substrate undergoes a chemical reaction by the excited photosensitized redox agent to generate a chemical product. As a result, the electrical resistance of the memory element changes.

  The electric resistance of the memory element having the reaction product changes as compared with the memory element before writing. As described above, data is written by applying a change in electric resistance between two conductive layers by applying a voltage. For example, when a layer including an organic compound to which no voltage is applied is set to “0” data, a large voltage is selectively applied to the layer including the organic compound of a desired memory element when writing “1” data. Apply to change resistance.

  Here, a case where data is written to the memory cell 221 in the m-th column and the n-th row will be described. In this case, when the bit line Bm in the mth column and the word line Wn in the nth row are selected by the row decoder 224a, the column decoder 226a, and the selector 226c, the transistor 240 included in the memory cell 221 in the mth column and the nth row is displayed. A voltage is applied between the first conductive layer 243 and the second conductive layer 245 of the memory cell so that the layer formed using a light-emitting material emits light. Note that the second conductive layer 245 of the memory element 241 is connected to the common electrode having the potential Vcom. The photosensitized redox agent in the layer containing the organic compound is excited by the emission energy. In addition, the substrate undergoes a chemical reaction by the excited photosensitized redox agent to generate a chemical product. As a result, the electrical resistance of the memory element changes.

  Next, an operation for reading data by applying a voltage will be described (see FIG. 16). Data is read by utilizing the fact that the electrical characteristics of the memory element 241 are different between the memory cell having the data “0” and the memory cell having the data “1”. For example, the electrical resistance of the memory element constituting the memory cell having data “0” is R0 at the read voltage, and the electrical resistance of the memory element constituting the memory cell having data “1” is R1 at the read voltage. A method of reading using the difference will be described. Note that R1 <R0. Here, the reading circuit 226b includes a resistance element 246 and a sense amplifier 247 as a configuration of a reading portion. The resistance element has a resistance value Rr, and R1 <Rr <R0. A transistor 254 may be used instead of the resistance element 246, and a clocked inverter 255 may be used instead of the sense amplifier (FIG. 16C). Of course, the circuit configuration is not limited to that shown in FIG.

  Data is read by applying a voltage between the first conductive layer 243 and the second conductive layer 245 and reading the electrical resistance of the layer 244 containing an organic compound. For example, when reading data from the memory cell 221 in the m-th column and the n-th row from the plurality of memory cells 221 included in the memory cell array 222, first, the row decoder 224a, the column decoder 226a, and the selector 226c are used to read the data in the m-th column. The bit line Bm and the n-th word line Wn are selected. Specifically, the row decoder 224a applies a predetermined voltage V24 to the word line Wy connected to the memory cell 221 to turn on the transistor 240. Further, the bit line Bx connected to the memory cell 221 is connected to the terminal P of the read 226b by the column decoder 226a and the selector 226c. As a result, the potential Vp of the terminal P is obtained by Vcom and V0, and Vcom and V0 are values determined by resistance division by the resistance element 246 (resistance value Rr) and the storage element 241 (resistance value R0 or R1). . Therefore, when the memory cell 221 has data “0”, Vp0 = Vcom + (V0−Vcom) × R0 / (R0 + Rr). When the memory cell 221 has data “1”, Vp1 = Vcom + (V0−Vcom) × R1 / (R1 + Rr). As a result, in FIG. 16B, Vref is selected to be between Vp0 and Vp1, and in FIG. 16C, the change point of the clocked inverter is selected to be between Vp0 and Vp1. Thus, Low / High (or High / Low) is output as the output potential Vout according to the data “0” / “1”, and reading can be performed.

  For example, the sense amplifier is operated at Vdd = 3V, and Vcom = 0V, V0 = 3V, and Vref = 1.5V. Assuming that R0 / Rr = Rr / R1 = 9 and the on-resistance of the transistor 240 can be ignored, when the data in the memory cell is “0”, Vp0 = 2.7V and Vout is output as high, and the memory cell When the data of “1” is “1”, Vp1 = 0.3V and Vout is output as Low. Thus, the memory cell can be read.

  Next, in the case where a transistor is used as the resistance element, an operation when data is read from the memory element by voltage application will be described with reference to a specific example in FIG.

  FIG. 21 shows a current-voltage characteristic 951 of the memory element in which data “0” is written to the memory element, a current-voltage characteristic 952 of the memory element in which data “1” is written, and the current of the resistance element 246. A voltage characteristic 953 is shown, and here, a case where a transistor is used as the resistance element 246 is shown. Further, a case where 3 V is applied between the first conductive layer 243 and the second conductive layer 245 as an operation voltage when reading data will be described.

  In FIG. 21, in a memory cell having a memory element in which data of “0” is written, an intersection 954 between the current-voltage characteristic 951 of the memory element and the current-voltage characteristic 953 of the transistor is an operating point. The potential of P is V2 (V). The potential of the node P is supplied to the sense amplifier 247, and the data stored in the memory cell is determined as “0” in the sense amplifier 247.

  On the other hand, in a memory cell having a memory element in which data of “1” is written, an intersection 955 between the current-voltage characteristic 952 of the memory element and the current-voltage characteristic 953 of the transistor serves as an operating point. The potential is V1 (V) (V1 <V2). The potential of the node P is supplied to the sense amplifier 247. In the sense amplifier 247, the data stored in the memory cell is determined as “1”.

  As described above, the data stored in the memory cell can be determined by reading the resistance-divided potential in accordance with the resistance value of the memory element 241.

  According to the above method, the voltage value is read by utilizing the difference in resistance value of the memory element 241 and the resistance division. However, the information included in the memory element 241 may be read using a current value.

Note that this embodiment mode can be freely combined with the above embodiment modes.

(Embodiment 10)
In this embodiment, an example of a semiconductor device typified by a wireless chip including the memory device described in the above embodiment will be described with reference to drawings.

  The semiconductor device described in this embodiment is characterized in that data can be read and written in a non-contact manner. A data transmission format is an electromagnetic which performs communication by mutual induction with a pair of coils arranged opposite to each other. There are roughly divided into a coupling system, an electromagnetic induction system that communicates using an induction electromagnetic field, and a radio system that communicates using radio waves, but any system may be used. There are two types of antennas used for data transmission. One is provided on a substrate provided with a transistor and a memory element, and the other is provided on a substrate provided with a transistor and a memory element. There is a case where a terminal portion is provided and an antenna provided on another substrate is connected to the terminal portion.

  First, a structural example of a semiconductor device in the case where an antenna is provided over a substrate provided with a plurality of elements and memory elements will be described with reference to FIGS.

  FIG. 18A illustrates a semiconductor device having a memory device formed of a passive matrix type. The semiconductor device includes a layer 351 including transistors 451 and 452 over a substrate 350, a memory element portion 352 formed over the layer 351 including transistors, and a conductive layer 353 functioning as an antenna.

Note that although the case where the memory element portion 352 and the conductive layer 353 functioning as an antenna are provided above the transistor 351 is shown here, the present invention is not limited to this structure, and the memory element portion 352 or the conductive layer 353 functioning as an antenna is provided. May be provided below the layer 351 including a transistor or in the same layer.

  The memory element portion 352 includes a plurality of memory elements 352a and 352b. The memory element 352a includes a first conductive layer 361 formed over the insulating layer 252, a layer 362a containing an organic compound that covers the first conductive layer 361 and the partition wall (insulating layer) 374, and a second conductive layer 362a. A conductive layer 363a. Note that a partition wall (insulating layer) 374 that covers part of the first conductive layer is formed. The memory element 352 b includes a first conductive layer 361 formed over the insulating layer 252, a first conductive layer 361, a layer 362 b containing an organic compound that covers the partition wall (insulating layer) 374, and a second A conductive layer 363b. Note that a partition wall (insulating layer) 374 that covers part of the first conductive layer is formed.

An insulating layer 366 that functions as a protective film is formed so as to cover the second conductive layers 363a and 363b and the conductive layer 353 that functions as an antenna. In addition, the first conductive layer 361 in which the memory element portion 352 is formed is connected to the wiring of the transistor 452. The memory element portion 352 can be formed using a material or a manufacturing method similar to those of the memory element described in the above embodiment.

  In the memory element portion 352, as described in the above embodiment mode, the first conductive layer 361 and the layers 362a and 362b containing an organic compound or the layers 362a and 362b containing an organic compound and the second An element having a rectifying property may be provided between the conductive layers 363a and 363b. As the element having a rectifying property, the element described in Embodiment Mode 7 can be used.

  Here, the conductive layer 353 functioning as an antenna is provided over the conductive layer 360 formed using the same layer as the second conductive layers 363a and 363b. Note that a conductive layer functioning as an antenna may be formed in the same layer as the second conductive layers 363a and 363b. The conductive layer 353 functioning as an antenna is connected to the source wiring or the drain wiring of the transistor 451.

  As a material of the conductive layer 353 functioning as an antenna, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), molybdenum (Mo), cobalt (Co), copper (Cu), aluminum (Al ), Manganese (Mn), titanium (Ti), or the like, or an alloy containing a plurality of such elements can be used. As a method for forming the conductive layer 353 functioning as an antenna, various printing methods such as vapor deposition, sputtering, CVD, screen printing, and gravure printing, a droplet discharge method, or the like can be used.

  As the transistors 451 and 452 included in the layer 351 including a transistor, the transistors 240 and 262 described in Embodiment 8 can be used as appropriate.

  In addition, a separation layer, a layer 351 having a transistor, a memory element portion 352, and a conductive layer 353 functioning as an antenna are formed over a substrate, and a layer 351 having a transistor is formed using the separation method described in Embodiment 8 as appropriate. The element portion 352 and the conductive layer 353 functioning as an antenna may be separated and attached to a flexible substrate with an adhesive layer. As the flexible substrate, a thermoplastic resin layer film, a paper made of a fibrous material, a base film, or the like shown in the substrate 30 of Embodiment 1 is used, so that the storage device is small, thin, and lightweight. Can be achieved.

  FIG. 18B illustrates an example of a semiconductor device including an active matrix memory device. Note that FIG. 18B will be described with respect to portions different from those in FIG.

  A semiconductor device illustrated in FIG. 18B includes a layer 351 including transistors 451 and 452 over a substrate 350, and a memory element portion 356 and a conductive layer 353 functioning as an antenna above the layer 351 including transistors. Note that here, the transistor 452 which functions as a switching element of the memory element portion 356 is provided in the same layer as the transistor 451, and the memory element portion 356 and the conductive layer 353 which functions as an antenna are provided above the layer 351 including the transistor. Although it is shown, the present invention is not limited to this structure and may be provided above or below the layer 351 having a transistor, or the memory element portion 356 or the conductive layer 353 functioning as an antenna may be provided below the layer 351 having a transistor or the same It is also possible to have in the layer.

  The memory element unit 356 includes memory elements 356a and 356b. The memory element 356 a includes a first conductive layer 371 a formed over the insulating layer 252, a layer 372 containing an organic compound that covers the first conductive layer 371 a and the partition wall (insulating layer) 374, and a second conductive layer 373. Note that a partition wall (insulating layer) 374 that covers part of the first conductive layer 371a is formed. The memory element 356b includes a first conductive layer 371b formed over the insulating layer 252, a layer 372 containing an organic compound that covers the first conductive layer 371b and the partition wall (insulating layer) 374, and a second conductive layer 373. Note that a partition wall (insulating layer) 374 that covers part of the first conductive layer 371b is formed. Here, the first conductive layer 371a and the first conductive layer 371b are connected to the wirings of the transistors. That is, each memory element is connected to one transistor.

Note that the memory elements 356a and 356b can be formed using any of the materials and manufacturing methods described in Embodiments 1 to 7. In the memory elements 356a and 356b, as described above, between the first conductive layers 371a and 371b and the layer 372 containing an organic compound, or between the layer 372 containing an organic compound and the second conductive layer 373, An element having a rectifying property may be provided between them.

  In addition, as described above, the conductive layer formed in the transistor-containing layer 351, the conductive layer formed in the memory element portion 356, and the conductive layer 353 functioning as an antenna can be formed by vapor deposition, sputtering, CVD, printing, or liquid. It can be formed using a droplet discharge method or the like. Note that a different method may be used depending on each place.

  A peeling layer, a layer 351 having a transistor, a memory element portion 356, and a conductive layer 353 functioning as an antenna are formed over a substrate, and the layer 351 having a transistor and a memory element portion are appropriately formed using the peeling method described in Embodiment 8. 356 and the conductive layer 353 functioning as an antenna may be peeled off and attached to a flexible substrate with an adhesive layer.

Note that a sensor connected to the transistor may be provided. Examples of the sensor include an element that detects temperature, humidity, illuminance, gas (gas), gravity, pressure, sound (vibration), acceleration, and other characteristics by physical or chemical means. The sensor is typically formed of an element such as a resistance element, a capacitive coupling element, an inductive coupling element, a photovoltaic element, a photoelectric conversion element, a thermoelectric element, a transistor, a thermistor, or a diode.

  Next, one structure of a semiconductor device including a layer having a transistor, a terminal portion connected to the transistor, a first substrate having a memory element, and a second substrate on which an antenna connected to the terminal portion is formed An example will be described with reference to FIG. Note that with respect to FIG. 19, portions different from FIG. 18 will be described.

  FIG. 19A illustrates a semiconductor device having a passive matrix memory device. The semiconductor device includes a layer 351 having a transistor formed over a substrate 350, a memory element portion 352 formed above the layer 351 having a transistor, a connection terminal 368 connected to the transistor 451, and a conductive layer functioning as an antenna. The conductive layer 357 and the connection terminal 368 are connected to each other with conductive particles. Note that here, the case where the memory element portion 352 is provided above the layer 351 having a transistor is shown; however, the present invention is not limited to this structure, and the memory element portion 352 is provided below the layer 351 having a transistor or in the same layer. May be.

  The memory element portion 352 can be formed using the memory element portion 352 having the structure illustrated in FIG.

  In addition, the substrate 365 including the transistor 351 and the memory element portion 352 and the substrate 365 provided with the conductive layer 357 functioning as an antenna are attached to each other with a resin 375 having adhesiveness. The layer 351 including a transistor and the conductive layer 357 are electrically connected through conductive particles 359 included in the resin 375. Further, a conductive layer such as a silver paste, a copper paste, or a carbon paste or a method of performing solder bonding is used to provide a layer 351 having a transistor, a substrate 350 having a memory element portion 352, and a conductive layer 357 functioning as an antenna. The obtained substrate 365 may be attached.

  FIG. 19B illustrates a semiconductor device provided with the memory device described in Embodiment 9, in which a layer 351 including transistors including transistors 451 and 452 formed over a substrate 350 and a layer including transistors are formed. 351 includes a memory element portion 356 formed above 351, a connection terminal 368 connected to the transistor 451, and a substrate 365 over which a conductive layer 357 functioning as an antenna is formed. The conductive layer 357 and the connection terminal are conductive. Connected by particles. Note that here, a case where the transistor 451 is included in the same layer as the transistor 451 in the layer 351 including the transistor and the conductive layer 357 functioning as an antenna is provided above the layer 351 including the transistor is shown. Without limitation, the memory element portion 356 may be provided below the layer 351 including a transistor or in the same layer.

  The memory element portion 356 can be formed using memory elements 356a and 356b having the structure illustrated in FIG.

  19B, a substrate 350 provided with a layer 351 including a transistor and a memory element portion 356 and a substrate 365 provided with a conductive layer 357 functioning as an antenna are attached with a resin 375 including conductive particles 359. Adapted. In addition, the conductive layer 357 and the connection terminal are connected by conductive particles.

  Further, a peeling layer, a layer 351 having a transistor, and a memory element portion 356 are formed over a substrate, and the layer 351 having a transistor and the memory element portion 356 are peeled off appropriately using the peeling method described in Embodiment 9 to be flexible. Alternatively, an adhesive layer may be attached to the substrate 461 having a property.

Further, the memory element portions 352 and 356 may be provided over the substrate 365 provided with a conductive layer functioning as an antenna. In other words, the first substrate over which a layer including a transistor is formed and the second substrate over which a conductive layer functioning as a memory element portion and an antenna are formed may be bonded to each other with a resin containing conductive particles. Further, similarly to the semiconductor device illustrated in FIGS. 18A and 18B, a sensor connected to a transistor may be provided.

Note that this embodiment can be freely combined with the above embodiment.

(Embodiment 11)
In this embodiment, a light-emitting material that can be used for the memory element described in any of Embodiments 1 to 6, the storage device in Embodiments 8 and 9, and the semiconductor device in Embodiment 10 is described below. .

  For the light-emitting element portions described in Embodiments 5 and 6, a light-emitting element using an inorganic compound as a light-emitting material can be used. Typically, there is an inorganic EL element using electroluminescence.

Inorganic EL elements are classified into a dispersion-type inorganic EL element and a thin-film inorganic EL element depending on the element structure. The former has an electroluminescent layer in which particles of a luminescent material are dispersed in a binder, and the latter has an electroluminescent layer made of a thin film of luminescent material, but is accelerated by a high electric field. This is common in that it requires more electrons. Note that the obtained light emission mechanism includes donor-acceptor recombination light emission using a donor level and an acceptor level, and localized light emission using inner-shell electron transition of a metal ion. In general, the dispersion-type inorganic EL often has donor-acceptor recombination light emission, and the thin-film inorganic EL element often has localized light emission.

A light-emitting material that can be used in this embodiment mode includes a base material and an impurity element that serves as a light-emission center. By changing the impurity element to be contained, light emission of various colors can be obtained. As a method for manufacturing the light-emitting material, various methods such as a solid phase method and a liquid phase method (coprecipitation method) can be used. Also, spray pyrolysis method, metathesis method, precursor thermal decomposition method, reverse micelle method, method combining these methods with high temperature firing, liquid phase method such as freeze-drying method, etc. can be used.

The solid phase method is a method in which a base material and an impurity element or a compound containing the impurity element are weighed, mixed in a mortar, heated and fired in an electric furnace, reacted, and the base material contains the impurity element. The firing temperature is preferably 700 to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state. Although firing at a relatively high temperature is required, it is a simple method, so it has high productivity and is suitable for mass production.

The liquid phase method (coprecipitation method) is a method in which a base material or a compound containing the base material and an impurity element or a compound containing the impurity element are reacted in a solution, dried, and then fired. The particles of the luminescent material are uniformly distributed, and the reaction can proceed even at a low firing temperature with a small particle size.

As a base material used for the light-emitting material, sulfide, oxide, or nitride can be used. Examples of the sulfide include zinc sulfide (ZnS), cadmium sulfide (CdS), calcium sulfide (CaS), yttrium sulfide (Y ₂ S ₃ ), gallium sulfide (Ga ₂ S ₃ ), strontium sulfide (SrS), sulfide. Barium (BaS) or the like can be used. As the oxide, for example, zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), or the like can be used. As the nitride, for example, aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN), or the like can be used. Furthermore, zinc selenide (ZnSe), zinc telluride (ZnTe), and the like can also be used, such as calcium sulfide-gallium sulfide (CaGa ₂ S ₄ ), strontium sulfide-gallium (SrGa ₂ S ₄ ), barium sulfide-gallium (BaGa). _It may be a ternary mixed crystal such as ₂ S ₄ ).

As the emission center of localized emission, manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), europium (Eu), cerium (Ce), praseodymium (Pr) or the like can be used. Note that a halogen element such as fluorine (F) or chlorine (Cl) may be added as charge compensation.

On the other hand, a light-emitting material containing a first impurity element that forms a donor level and a second impurity element that forms an acceptor level can be used as the emission center of donor-acceptor recombination light emission. Examples of the first impurity element include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), boron (B), aluminum (Al), gallium (Ga), indium (In), and thallium. (Tl) or the like can be used. As the second impurity element, for example, a metal element such as copper (Cu), silver (Ag), gold (Au), or platinum (Pt), silicon (Si), or the like can be used.

In the case where a light-emitting material for donor-acceptor recombination light emission is synthesized using a solid-phase method, a base material, a first impurity element or a compound containing the first impurity element, a second impurity element, or a second impurity element Each compound containing an impurity element is weighed and mixed in a mortar, and then heated and fired in an electric furnace. As the base material, the above-described base material can be used, and examples of the first impurity element or the compound containing the first impurity element include fluorine (F), chlorine (Cl), and aluminum sulfide (Al ₂ S). ₃ ) or the like, and examples of the second impurity element or the compound containing the second impurity element include copper (Cu), silver (Ag), copper sulfide (Cu ₂ S), and silver sulfide (Ag). ₂ S) or the like can be used. The firing temperature is preferably 700 to 1500 ° C. This is because the solid phase reaction does not proceed when the temperature is too low, and the base material is decomposed when the temperature is too high. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state.

In addition, as an impurity element in the case of using a solid phase reaction, a compound including a first impurity element and a second impurity element may be used in combination. In this case, since the impurity element is easily diffused and the solid-phase reaction easily proceeds, a uniform light emitting material can be obtained. Further, since no extra impurity element is contained, a light-emitting material with high purity can be obtained. Examples of the compound composed of the first impurity element and the second impurity element include copper fluoride (CuF ₂ ), copper chloride (CuCl), copper iodide (CuI), copper bromide (CuBr), and nitride. Copper (Cu ₃ N), copper phosphide (Cu ₃ P), silver fluoride (AgF), silver chloride (AgCl), silver iodide (AgI), silver bromide (AgBr), gold chloride (AuCl ₃ ), Gold bromide (AuBr ₃ ), platinum chloride (PtCl ₂ ), or the like can be used.

Note that the concentration of these impurity elements may be 0.01 to 10 atom% with respect to the base material, and is preferably in the range of 0.05 to 5 atom%.

Alternatively, a light-emitting material containing a third impurity element may be used as a light-emitting material having a donor-acceptor recombination-type light emission center. Examples of the third impurity element include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), nitrogen (N), phosphorus (P), arsenic (As), and antimony. (Sb), bismuth (Bi), or the like can be used. In this case, the concentration of the third impurity element is preferably 0.05 to 5 atom% with respect to the base material. The light emitting material having such a configuration can emit light at a low voltage. Therefore, a light-emitting element that can emit light at a low driving voltage can be obtained, and a light-emitting element with reduced power consumption can be obtained. Further, an impurity element which becomes a light emission center of the above-described localized light emission may be included.

As such a light emitting material, for example, ZnS is used as a base material, Cl is used as a first impurity element, Cu is used as a second impurity element, Ga and As are used as a third impurity element, and light emission of localized light emission is further performed. It is also possible to use a light emitting material containing Mn as the center. In order to form such a light emitting material, the following method can be used. Mn is added to the light-emitting material (ZnS: Cu, Cl), and baked in vacuum for about 2 to 4 hours. The firing temperature is preferably 700 to 1500 ° C. The fired product is pulverized to a particle size of 5 to 20 μm, GaAs having a particle size of 1 to 3 μm is added and stirred. A luminescent material can be obtained by baking this mixture at about 500 to 800 ° C. for 2 to 4 hours in a nitrogen stream containing sulfur gas. By using this luminescent material and forming a thin film by vapor deposition or the like, it can be used as a light emitting layer of a light emitting element.

A light-emitting layer using the above-described material as a base material and using the above-described light-emitting material including the first impurity element, the second impurity element, and the third impurity element requires hot electrons accelerated by a high electric field. Without emitting light. That is, since it is not necessary to apply a high voltage to the light emitting element, a light emitting element that can operate with a low driving voltage can be obtained. In addition, since light can be emitted with a low driving voltage, a light-emitting element with reduced power consumption can be obtained. Further, an element that becomes another light emission center may be included.

In addition, the inorganic EL element uses the above-described material as a base material, and uses a light-emitting material including a light-emitting center using the second impurity element, the third impurity element, and the inner-shell electron transition of the metal ion described above. it can. In this case, the metal ion serving as the emission center is preferably 0.05 to 5 atomic% with respect to the base material. The concentration of the second impurity element is preferably 0.05 to 5 atomic% with respect to the base material. The concentration of the third impurity element is preferably 0.05 to 5 atomic% with respect to the base material. The light emitting material having such a structure can emit light at a low voltage. Accordingly, a light-emitting element that can emit light at a low driving voltage can be obtained, and thus a light-emitting element with reduced power consumption can be obtained. Further, an element that becomes another light emission center may be included.

In the case of a thin-film inorganic EL, the electroluminescent layer is a layer containing the above-described luminescent material, and is a physical vapor deposition method such as a resistance heating vapor deposition method, a vacuum vapor deposition method such as an electron beam vapor deposition (EB vapor deposition) method, a sputtering method, PVD), metal organic chemical vapor deposition (CVD), chemical vapor deposition (CVD) such as hydride transport low pressure CVD, atomic epitaxy (ALE), or the like.

FIGS. 26A to 26C illustrate an example of a thin-film inorganic EL element that can be used as a light-emitting element. 26A to 26C, the light-emitting element includes a first conductive layer 50, an electroluminescent layer 52, and a conductive layer 53 having a light-transmitting property.

A light-emitting element illustrated in FIGS. 26B and 26C has a structure in which an insulating layer is provided between the electrode layer and the electroluminescent layer in the light-emitting element in FIG. The light-emitting element illustrated in FIG. 26B includes an insulating layer 54 between the first conductive layer 50 and the electroluminescent layer 52, and the light-emitting element illustrated in FIG. 26C includes the first conductive layer 50. And an electroluminescent layer 52, and an insulating layer 54 b is provided between the light-transmitting conductive layer 53 and the electroluminescent layer 52. Thus, the insulating layer may be provided only between one of the pair of electrode layers sandwiching the electroluminescent layer, or may be provided between both. Further, the insulating layer may be a single layer or a stacked layer including a plurality of layers.

In FIG. 26B, the insulating layer 54 is provided so as to be in contact with the first conductive layer 50; however, the order of the insulating layer and the electroluminescent layer is reversed so that the light-transmitting conductive layer 53 is formed. An insulating layer 54 may be provided so as to be in contact with each other.

In the case of a dispersion-type inorganic EL, a particulate luminescent material is dispersed in a binder to form a film-like electroluminescent layer. When particles having a desired size cannot be obtained sufficiently by the method for manufacturing a light emitting material, the particles may be processed into particles by pulverization or the like in a mortar or the like. A binder is a substance for fixing a granular light emitting material in a dispersed state and maintaining the shape as an electroluminescent layer. The light emitting material is uniformly dispersed and fixed in the electroluminescent layer by the binder.

In the case of a dispersion-type inorganic EL, the electroluminescent layer can be formed by a droplet discharge method capable of selectively forming an electroluminescent layer, a printing method (screen printing, offset printing, etc.), a coating method such as a spin coating method, dipping, etc. It is also possible to use a method or a dispenser method. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm. In the electroluminescent layer including the light emitting material and the binder, the ratio of the light emitting material may be 50 wt% or more and 80 wt% or less.

FIGS. 27A to 27C illustrate an example of a dispersion-type inorganic EL element that can be used as a light-emitting element. A light-emitting element in FIG. 27A has a stacked structure of a first conductive layer 60, an electroluminescent layer 62, and a light-transmitting conductive layer 63, and a light-emitting material held in the electroluminescent layer 62 by a binder. 61 is included.

As a binder that can be used in this embodiment mode, an insulating material can be used, an organic material or an inorganic material can be used, and a mixed material of an organic material and an inorganic material can be used. As the organic insulating material, a polymer having a relatively high dielectric constant such as a cyanoethyl cellulose resin, or a resin such as polyethylene, polypropylene, polystyrene resin, silicone resin, epoxy resin, or vinylidene fluoride can be used. Alternatively, a heat-resistant polymer such as aromatic polyamide, polybenzimidazole, or siloxane resin may be used. Note that a siloxane resin corresponds to a resin including a Si—O—Si bond. Siloxane has a skeleton structure formed of a bond of silicon (Si) and oxygen (O). As a substituent, an organic group containing at least hydrogen (for example, an alkyl group or an aromatic hydrocarbon) is used. A fluoro group may be used as a substituent. Alternatively, an organic group containing at least hydrogen and a fluoro group may be used as a substituent. Moreover, resin materials such as vinyl resins such as polyvinyl alcohol and polyvinyl butyral, phenol resins, novolac resins, acrylic resins, melamine resins, urethane resins, and oxazole resins (polybenzoxazole) may be used. Moreover, a photocurable resin material or the like can be used. The dielectric constant can be adjusted by appropriately mixing fine particles of high dielectric constant such as barium titanate (BaTiO ₃ ) and strontium titanate (SrTiO ₃ ) with these resins.

Examples of the inorganic insulating material contained in the binder include silicon oxide (SiO _x ), silicon nitride (SiN _x ), silicon containing oxygen and nitrogen, aluminum nitride (AlN), aluminum containing oxygen and nitrogen, or aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), BaTiO ₃ , SrTiO ₃ , lead titanate (PbTiO ₃ ), potassium niobate (KNbO ₃ ), lead niobate (PbNbO ₃ ), tantalum oxide (Ta ₂ O ₅ ), tantalum Formed with a material selected from materials including barium oxide (BaTa ₂ O ₆ ), lithium tantalate (LiTaO ₃ ), yttrium oxide (Y ₂ O ₃ ), zirconium oxide (ZrO ₂ ), ZnS and other inorganic insulating materials. can do. By including an inorganic material having a high dielectric constant in the organic material (by addition or the like), the dielectric constant of the electroluminescent layer made of the light emitting material and the binder can be further controlled, and the dielectric constant can be further increased. .

In the manufacturing process, the light-emitting material is dispersed in a solution containing a binder, but as a solvent for the solution containing a binder that can be used in this embodiment, a method of forming an electroluminescent layer by dissolving the binder material (various types) A solvent capable of producing a solution having a viscosity suitable for a wet process) and a desired film thickness may be appropriately selected. For example, when a siloxane resin is used as a binder, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate (also referred to as PGMEA), 3-methoxy-3-methyl-1-butanol (also referred to as MMB) can be used. Etc. can be used.

The light-emitting element illustrated in FIGS. 27B and 27C has a structure in which an insulating layer is provided between the electrode layer and the electroluminescent layer in the light-emitting element in FIG. The light-emitting element illustrated in FIG. 27B includes an insulating layer 64 between the first conductive layer 60 and the electroluminescent layer 62, and the light-emitting element illustrated in FIG. 27C includes the first conductive layer 60. An insulating layer 64 a is provided between the electroluminescent layer 62 and the electroluminescent layer 62, and an insulating layer 64 b is provided between the light-transmitting conductive layer 63 and the electroluminescent layer 62. Thus, the insulating layer may be provided only between one of the pair of electrode layers sandwiching the electroluminescent layer, or may be provided between both. Further, the insulating layer may be a single layer or a stacked layer including a plurality of layers.

In FIG. 27B, the insulating layer 64 is provided so as to be in contact with the first conductive layer 60; however, the order of the insulating layer and the electroluminescent layer is reversed so that the light-transmitting conductive layer 63 is formed. An insulating layer 64 may be provided so as to be in contact with each other.

The first conductive layer 50, the light-transmitting conductive layer 53 in FIG. 26, the first conductive layer 60 in FIG. 27, and the light-transmitting conductive layer 63 are the first conductive layers shown in Embodiment Modes 5 and 6. The conductive layer 101 and the light-transmitting conductive layer 141 can be used as appropriate.

Insulating layers such as the insulating layer 54 in FIG. 26 and the insulating layer 64 in FIG. 27 are not particularly limited, but preferably have high insulation resistance, a dense film quality, and a high dielectric constant. It is preferable. For example, silicon oxide (SiO ₂ ), yttrium oxide (Y ₂ O ₃ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), tantalum oxide (Ta ₂ O ₅ ), Barium titanate (BaTiO ₃ ), strontium titanate (SrTiO ₃ ), lead titanate (PbTiO ₃ ), silicon nitride (Si ₃ N ₄ ), zirconium oxide (ZrO ₂ ), etc., a mixed film thereof, or two or more kinds thereof A laminated film can be used. These insulating films can be formed by sputtering, vapor deposition, CVD, or the like. The insulating layer may be formed by dispersing particles of these insulating materials in a binder. The binder material may be formed using the same material and method as the binder contained in the electroluminescent layer. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm.

Further, as the light-emitting material described in any of Embodiments 1 to 4, the base material and an impurity element which serves as a light emission center can be used as appropriate.

The light-emitting element described in this embodiment mode can emit light by applying a voltage between a pair of electrode layers sandwiching an electroluminescent layer, but can operate in either DC driving or AC driving.

Here, the configuration of the semiconductor device of this embodiment will be described with reference to FIG. As shown in FIG. 22A, the semiconductor device 20 of this embodiment has a function of communicating data without contact, and includes a power supply circuit 11, a clock generation circuit 12, a data demodulation / modulation circuit 13, and other circuits. A control circuit 14, an interface circuit 15, a storage device 16, a bus 17, and an antenna 18.

Further, as shown in FIG. 22B, the semiconductor device 20 of this embodiment has a function of communicating data without contact, and includes a power supply circuit 11, a clock generation circuit 12, a data demodulation / modulation circuit 13, and the like. In addition to the control circuit 14, the interface circuit 15, the storage device 16, the bus 17, and the antenna 18, the central processing unit 71 may be included.

Further, as shown in FIG. 22C, the semiconductor device 20 of this embodiment has a function of communicating data without contact, and includes a power supply circuit 11, a clock generation circuit 12, a data demodulation / modulation circuit 13, and the like. In addition to the control circuit 14, the interface circuit 15, the storage device 16, the bus 17, the antenna 18, and the central processing unit 71, a detection unit 72 including a detection element 73 and a detection control circuit 74 may be provided.

The semiconductor device of this embodiment includes a power supply circuit 11, a clock generation circuit 12, a data demodulation / modulation circuit 13, a control circuit 14 for controlling other circuits, an interface circuit 15, a storage device 16, and a transistor in a layer having transistors. In addition to the bus 17, the antenna 18, and the central processing unit 71, the detection unit 72 including the detection element 73, the detection control circuit 74, and the like can be configured to form a small and multi-functional semiconductor device.

  The power supply circuit 11 is a circuit that generates various power supplies to be supplied to each circuit inside the semiconductor device 20 based on the AC signal input from the antenna 18. The clock generation circuit 12 is a circuit that generates various clock signals to be supplied to each circuit inside the semiconductor device 20 based on the AC signal input from the antenna 18. The data demodulation / modulation circuit 13 has a function of demodulating / modulating data communicated with the reader / writer 19. The control circuit 14 has a function of controlling the storage device 16. The antenna 18 has a function of transmitting / receiving electromagnetic waves or radio waves. The reader / writer 19 controls communication and control with the semiconductor device and processing related to the data. The semiconductor device is not limited to the above-described configuration, and may be a configuration in which other elements such as a power supply voltage limiter circuit and hardware dedicated to cryptographic processing are added.

  The storage device 16 has one or more selected from the storage devices described in the eighth embodiment or the ninth embodiment. Since a memory element having a layer containing an organic compound can simultaneously achieve downsizing, thinning, and large capacity, by providing the memory device 16 as a memory element having a layer containing an organic compound, A reduction in size and weight can be achieved.

The detection unit 72 can detect temperature, pressure, flow rate, light, magnetism, sound wave, acceleration, humidity, gas component, liquid component, and other characteristics by physical or chemical means. The detection unit 72 includes a detection element 73 that detects a physical quantity or a chemical quantity, and a detection control circuit 74 that converts the physical quantity or the chemical quantity detected by the detection element 73 into an appropriate signal such as an electrical signal. Yes. The detection element 73 can be formed of a resistance element, a capacitive coupling element, an inductive coupling element, a photovoltaic element, a photoelectric conversion element, a thermoelectric element, a transistor, a thermistor, a diode, or the like. A plurality of detection units 72 may be provided. In this case, a plurality of physical quantities or chemical quantities can be detected simultaneously.

The physical quantity here refers to temperature, pressure, flow rate, light, magnetism, sound wave, acceleration, humidity, etc., and the chemical quantity refers to chemicals such as components contained in gas components such as gases and liquids such as ions. It refers to substances. In addition, the chemical amount includes organic compounds such as specific biological substances (for example, blood glucose level contained in blood) contained in blood, sweat, urine and the like. In particular, when a chemical amount is to be detected, a specific substance is inevitably selectively detected. Therefore, a substance that selectively reacts with a substance to be detected is provided in the detection element 73 in advance. . For example, when detecting a biological material, it is preferable to provide an enzyme, an antibody molecule, a microbial cell, or the like that selectively reacts with the biological material to be detected by the detection element 73 in a polymer or the like.

  According to this embodiment, the semiconductor device 20 functioning as a wireless chip can be formed. Applications of wireless chips are wide-ranging. For example, banknotes, coins, securities, bearer bonds, certificates (driver's license, resident card, etc., see FIG. 24A), packaging containers (wrapping paper and Bottle, etc., see FIG. 24C), recording medium (DVD software, video tape, etc., see FIG. 24B), vehicles (bicycle, etc., see FIG. 24D), personal items (bags, glasses, etc.) ), Foods, plants, animals, human bodies, clothing, daily necessities, electronic devices, etc. and goods such as luggage tags (see FIGS. 24E and 24F) for use. be able to. Electronic devices refer to liquid crystal display devices, EL display devices, television devices (also simply referred to as televisions, television receivers, television receivers), mobile phones, and the like.

  The semiconductor device 20 of the present embodiment is fixed to an article by being mounted on a printed board, pasted on the surface, or embedded. For example, a book is embedded in paper, and a package made of an organic resin is embedded in the organic resin, and is fixed to each article. Since the semiconductor device 20 of the present embodiment realizes small size, thinness, and light weight, the design of the article itself is not impaired even after being fixed to the article. Further, by providing the semiconductor device 20 of the present embodiment on bills, coins, securities, bearer bonds, certificates, etc., an authentication function can be provided, and forgery can be prevented by utilizing this authentication function. be able to. Also, by providing the semiconductor device of this embodiment in packaging containers, recording media, personal items, foods, clothing, daily necessities, electronic devices, etc., it is possible to improve the efficiency of systems such as inspection systems. .

Next, one mode of an electronic device in which the semiconductor device of this embodiment is mounted will be described with reference to the drawings. The electronic device illustrated here is a mobile phone, which includes housings 2700 and 2706, a panel 2701, a housing 2702, a printed wiring board 2703, operation buttons 2704, and a battery 2705 (see FIG. 23). The panel 2701 is detachably incorporated in the housing 2702, and the housing 2702 is fitted on the printed wiring board 2703. The shape and dimensions of the housing 2702 are changed as appropriate in accordance with the electronic device in which the panel 2701 is incorporated. A plurality of packaged semiconductor devices are mounted on the printed wiring board 2703, and the semiconductor device 20 of this embodiment can be used as one of them. The plurality of semiconductor devices mounted on the printed wiring board 2703 have any one function of a controller, a central processing unit (CPU), a memory, a power supply circuit, a sound processing circuit, a transmission / reception circuit, and the like.

The panel 2701 is connected to the printed wiring board 2703 through the connection film 2708. The panel 2701, the housing 2702, and the printed wiring board 2703 are housed in the housings 2700 and 2706 together with the operation buttons 2704 and the battery 2705. A pixel region 2709 included in the panel 2701 is arranged so as to be visible from an opening window provided in the housing 2700.

As described above, the semiconductor device of this embodiment is characterized in that it is small, thin, and lightweight. With the above characteristics, it is possible to effectively use the limited space inside the casings 2700 and 2706 of the electronic device. it can.

  In addition, since the semiconductor device of this embodiment includes a memory element having a simple structure in which a layer containing an organic compound that is changed by voltage application from the outside is sandwiched between a pair of conductive layers, an electronic device using an inexpensive semiconductor device Equipment can be provided. In addition, since the semiconductor device of this embodiment can be easily integrated, an electronic device using the semiconductor device including a large-capacity memory device can be provided.

  In addition, the memory device included in the semiconductor device of this embodiment performs data writing by applying voltage from the outside, is nonvolatile, and can additionally write data. With the above feature, forgery due to rewriting can be prevented, and new data can be added and written. Therefore, an electronic device using a semiconductor device that achieves high functionality and high added value can be provided.

Note that the housings 2700 and 2706 are examples of the appearance of a mobile phone, and the electronic device according to the present embodiment can be transformed into various modes depending on the function and application.

FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. FIG. 6 is a cross-sectional view illustrating a memory element of the present invention. 3A and 3B illustrate a memory device of the present invention. 4A and 4B are a top view and cross-sectional views illustrating a memory device of the present invention. 3A and 3B illustrate a memory device of the present invention. 4A and 4B are a top view and cross-sectional views illustrating a memory device of the present invention. FIG. 6 is a cross-sectional view illustrating a semiconductor device of the present invention. FIG. 6 is a cross-sectional view illustrating a semiconductor device of the present invention. FIG. 6 is a cross-sectional view illustrating a semiconductor device of the present invention. 10A and 10B illustrate current-voltage characteristics of a memory element and a resistance element. 8A and 8B illustrate a structure example of a semiconductor device of the present invention. 6A and 6B illustrate an electronic device including a semiconductor device of the present invention. 4A and 4B each illustrate a usage pattern of a semiconductor device of the invention. FIG. 10 is a cross-sectional view illustrating a thin film transistor applicable to the present invention. FIG. 6 is a cross-sectional view illustrating a light-emitting element that can be applied to the present invention. FIG. 6 is a cross-sectional view illustrating a light-emitting element that can be applied to the present invention.

Claims (13)

A first conductive layer, a second conductive layer, is formed between the first conductive layer and the second conductive layer, and, photosensitizer redox agent, and the photosensitizer redox And a layer containing an organic compound having a substrate that undergoes a photosensitized oxidation-reduction reaction with an agent. In claim 1,
The photosensitized redox agent is excited by energy generated by recombination of holes and electrons generated by applying a voltage to the first conductive layer and the second conductive layer. A storage device, wherein a photosensitized redox reaction occurs in at least a part of the substrate by a sensitized redox agent to generate a reaction product having a conductivity different from that of the substrate. A first conductive layer, a second conductive layer, a material formed between the first conductive layer and the second conductive layer and having a light emitting property, a photosensitized redox agent, and A memory device comprising: a memory element including a layer containing an organic compound having a substrate that at least partially undergoes a photosensitized redox reaction with the photosensitized redox agent. In claim 3,
The memory device characterized in that the layer containing an organic compound is formed by laminating a layer formed of a light-emitting material and a layer formed of a photosensitized redox agent and a substrate. In claim 3 or claim 4,
The photosensitized redox agent emits light by recombination of holes and electrons generated by applying a voltage to the first conductive layer and the second conductive layer in the light emitting material. The excited state is caused by energy, and the photosensitized redox agent in the excited state causes a photosensitized redox reaction in at least a part of the substrate, and a reaction product having a conductivity different from that of the substrate is generated. A storage device. The first conductive layer has a second conductive layer having a light transmitting property, and a third conductive layer,
In between the first conductive layer and the second conductive layer, a layer containing a first organic compound is formed of a material having a light-emitting property,
In between the front Stories second conductive layer and the third conductive layer, the second having a substrate at least partially to sense redox reaction rose light by the photosensitizer redox agent and said photosensitizer redox agent A memory device having a memory element including a layer containing any organic compound. In claim 6,
The photosensitizer redox agent, becomes excited by the energy due to the recombination of holes and electrons generated by applying a voltage to the first conductive layer and before Symbol second conductive layer, the excited state A storage device, wherein a photosensitized redox reaction causes a photosensitized redox reaction in at least a part of the substrate to generate a reaction product having a conductivity different from that of the substrate. In any one of Claims 1 thru | or 5,
A memory device comprising a diode connected to the first conductive layer or the second conductive layer. In any one of Claims 6 to 8,
A memory device comprising a diode connected to the first conductive layer or the third conductive layer.   10. A semiconductor device comprising: a memory cell array in which the memory elements according to claim 1 are arranged in a matrix; and a write circuit. A memory cell array having memory cells constituted by storage elements and transistors are arranged in a matrix according to any one of claims 1 to 9, wherein a and a write circuit. In any one of Claims 1 to 11,
A semiconductor device comprising: a conductive layer functioning as an antenna; and a transistor electrically connected to the conductive layer functioning as the antenna. In claim 12,
A semiconductor device comprising one or more of a reading circuit, a power supply circuit, a clock generation circuit, a data demodulation / modulation circuit, a control circuit, and an interface circuit.

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